CHEMISTRY SOLUTIONS
GRADE VI, VII, VIII & IX
ALL CHAPTERS
Propel Academy
CHAPTER 1 MATTER AND ITS
PROPERTIES
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 b It has no mass and volume
2 b It has no volume and mass
3 a He found Brownian motion
4 c These two have volume and mass
5 c Other used to measure liquid and length
6 D Matter has mass and volume
Serial No.
Answers Explanations
1 b Solid, liquid and gas
2 c Liquid water cannot persist at the Moon's surface
3 d Solid, liquid and gas phases changed due to temperature and pressure
4 d Freezing and melting points are same
5 a Temperature is constant
6 a Boiling means it absorbs water
Introductory Exercise 1
Introductory Exercise 2
Serial No.
Answers Explanations
1 c Stone is a solid
2 c Plastic is a solid and foam is not a liquid
3 d We can’t change the mass by twisting the balloon
4 b Water has no definite volume and shape
5 c Object C has largest volume
6 c Both are matters
7 b Milk has no definite volume
8 a Ice cube melt and form liquid
9 b Cotton bud is solid and juice is a liquid
Introductory Exercise 3
Class VI C1:Matter and its properties
© Dr. Ravi’s Educational Research and Development Center 2
7 c Freezing and melting points are same
8 a The strength of bond also loses
9 b Latent means hidden
10 b For 1 kg it needs 3.34
11 a Condensation and boiling point same
12 d Water vapour at 373 has more energy
13 a It can undergo sublimation
14 d We can change all with temperature
15 b We can change only gas
Serial No.
Answers Explanations
1 d All these are gaseous state
2 a Solid to liquid by melting and liquid to gas by boiling
3 b Gaseous to liquid is condensation
4 d Boiling solid absorbs heat
5 c Non-living things are also matter
6 a Fire is energy
7 b If we pour hot water, the glass will expand
8 c It has no volume and mass
9 a Solids have definite volume, shape and mass
10 a CO2 never support burning
11 a Shadows and reflections are not matter
12 c Sound is not a matter, oil has no definite shape
13 c The shape of containers are different
14 d The ice melt into water
15 d That’s why it absorb water
16 a heating air molecules causes them to get excited
17 d It has no definite volume, it is a liquid
18 d Milk already hot, so it lose its heat
Serial No.
Answers Explanations
1 C Solids have a definite shape
2 D The particles in a liquid are not close together with regular arrangement
3 B
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Statement Type
Class VI C1:Matter and its properties
© Dr. Ravi’s Educational Research and Development Center 3
Serial No.
Answers Explanations
1 c Oxygen is in gaseous state
2 d It has definite shape
3 b It assumes the shape of the container
4 a It is the fourth state of matter
1 c Iodine is a sublimate
2 d Water changes into water vapour by evaporation
3 a Condensation means water change to ice
4 b Boiling point ice to water and water to steam
Serial No.
Answers Explanations
1 a Evaporation can takes place at any temperature
2 b After rain humidity will increase
3 d The solid form undergo sublimation is called sublime
4 a Ammonium chloride undergo sublimation process
5 c Intermolecular spaces are large in gases
Serial No.
Answers Explanations
1 c, d Heat and light are not matter
2 a, c, d Matter cannot be seen
3 a, b, c We can’t make or destroy mass
4 a,c Air lost from one balloon
5 b, c Air can be compressed
6 a, c It contain more water vapour
7 a, d It never decrease its volume
8 c, d Boiling absorb heat
9 a Substance z is not water
10 a, c Cooling make water droplets
11 b, d Solid has a definite shape
12 d This is a liquid so takes the shape of a container
13 b Definite shape only ball have
14 a, b, c, d Book is a matter
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
Class VI C1:Matter and its properties
© Dr. Ravi’s Educational Research and Development Center 4
15 a, c All are matter and has same mass
Serial No.
Answers Explanations
1 d Water cannot be compressed
2 b It is in balanced state
3 d Air can be compressed
4 d So melting is very slowly
5 b Water occupy some space
6 a These are different states of matter
7 b Three objects have three different shapes
8 a Between 15 and 110 x is liquid,
9 a Because ice is a solid
10 b Matter is more in cotton
11 b,c They are closely packed
12 b 200 water is there
13 a Matter occupy space
14 a It is in balanced state as they have the same volume
15 d Air can be compressed
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 2 BASICS
OFCHEMISTRY
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d Symbol of Aluminium Al
2 a Symbol of Boron is B
3 c Aurum is the name of gold
4 d Sodium symbol Na
5 C Iron for Ferrrum
6 c Cupperum is the Latin name of Copper
7 c Cl is the name of chlorine
Serial No.
Answers Explanations
1 a They have no charge
2 a Neutron have no charge
3 b Atomic number z
4 d The number of protons in the nucleus of an atom
5 a Mass number – atomic number
6 b Mass number A
7 d The atomic number of sodium is 11
Introductory Exercise 1
Serial No.
Answers Explanations
1 d Both protons and neutrons
2 a, b It contain a single proton and single electron
3 d It contains 3 protons, 4 neutrons and 3 electrons
4 d Hydrogen is lighter
5 b Electrons are 1800 times smaller
6 a Both have opposite charge
7 c Neutrons have no force
8 b This is the value of radius
Introductory Exercise 2
LEVEL 1 Exercise 1 Single correct objective questions
Class VI C2:Basics of Chemistry
© Dr. Ravi’s Educational Research and Development Center 2
8 b One unit negative charge
9 b Electrons are 1837 times smaller
10 b An atom is the smallest particle of an element that has the propertiesof that
11 b A molecule has all the properties like a compound
12 d We can’ t say the nature
13 d Water is a compound
Serial No.
Answers Explanations
1 b Water contains three atoms
2 d Gold is an alloy
3 b Mass number denoted by A
Serial No.
Answers Explanations
1 b Copper is Cu
2 d Lead is Pb
3 a Mercury is Hg
4 c Gold is Aurum
1 c Helium is an element
2 d CO2 is a compound
3 b Air is a mixture of all gas
4 a He+ is an ion
Serial No.
Answers Explanations
1 b Protons present inside and electron outside
2 d Protons are positively charged particle
3 a Force increased by increasing the charge
4 a Atomic number is the number of protons
Exercise 2 Statement Type
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
Class VI C2:Basics of Chemistry
© Dr. Ravi’s Educational Research and Development Center 3
Serial No.
Answers Explanations
1 d Proton is a particle
2 b, c It is present inside the nucleus
3 a, b, d Only one proton in hydrogen
4 b, d Salt water is a mixture of salt and water
5 a, b Na for sodium and K for Potassium
6 c 20 represents atomic number, 40 means mass number
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Serial No.
Answers Explanations
1 d Au for gold, Hg mercury
2 c Li for Lithium
3 b Au for Gold
4 a Pb for lead
5 a Ag for silver
6 a Calcium atomic weight is 40
7 a Magnesium contain 12, 13 or 14 neutrons
8 d Helium has 4 number of protons
9 b Atomic number means number of protons
10 d atomic weight – atomic number= number of neutrons
11 d Equal number of protons and electrons
12 a Protons, electrons and neutrons
13 a John Dalton assumed atoms to be tiny particles
14 a Inside the nucleus only protons and neutrons present
15 d Atomic weight means number of protons + neutrons
16 c Neon has 10 number of electrons
17 a Inside orbit called core
18 b Outside orbit contain 8 electrons
Propel Academy
CHAPTER 3 WATER AND ITS PROPTERTIES
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No
Answers Explanation
1 b Water contains hydrogen and oxygen
2 b Water contains hydrogen and oxygen
3 b Steam is essentially water in a gas-like state.
4 c Water changes into steam by 1000c
5 a It is condensation
6 d All are natural sources
7 c Our body weight contains 70% water
Serial No
Answers Explanation
1 d B & D processes are condensation
2 b C is the step which has no change in the state
3 d Water can change from one state to another
4 c Through condensation gas can change to liquid and liquid can change to solid
5 d Hailstones are snow.
6 d Because it has a definite shape
7 b After 1 hr its shape changed
8 d In ice water it ice cube melt slowly
9 a 00c water in solid state
10 b, c X did not change its shape in both pictures.
Serial No
Answers Explanation
1 b Ice is frozen water
2 d Oxygen is anion and hydrogen is cation
3 b Both the statements are correct
4 Wrong Question
Introductory Exercise 1
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Statement Type
Calss VI C3:Water and its properties
© Dr. Ravi’s Educational Research and Development Center 2
Serial No
Answers Explanation
1 a, b Salt can reduce melting point
2 b, c It can increase the amount of water vapour
3 c, d Sweating of animal is not related with water cycle
4 b, d Plants reduce pollution
5 b, c, d Remove trees cause soil erosion
6 a, c They is no relation with taste and colour
7 b, d If heat is not there, water can’t change its state
8 a,b, c, d Humidity more means evaporation less
9 a, b,d Don’t waste water
Serial No
Answers Explanation
1 d Only hard water form sticky scum
2 a Increase level CO2 cause global warming
3 b Eutrophication leads to the death of fish
4 b Ice has a regular crystalline structure
5 d Two atom hydrogen and one atom of oxygen
Serial No
Answers Explanation
1 c The amount of water vapour more in air
2 b We have to take same amount of water
3 d The amount of water will increase
4 d Same level of water
5 b Cube changed to water then gas
6 d So it can easily dry
Composition of Air
Serial No.
Answers Explanation
1 b Air occupies empty spaces
2 c Breathing and combustion need oxygen
3 d All others are noble gases
Exercise 3 One or more than one correct options
LEVEL 2 Exercise 4 Assertion and reason
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Introductory Exercise 2
Calss VI C3:Water and its properties
© Dr. Ravi’s Educational Research and Development Center 3
4 c Living things need oxygen
5 a Villages are good for health
6 d Air can expand, it has mass
Serial No.
Answers Explanation
1 c Sail boats are not flying in air
2 b Plants can absorb only nitrates
3 c Main part of protein is nitrogen
4 b The size of that bag is small
5 c Water vapour present in the air forms mist
6 c Water and ice cannot be compressed
7 a Option a. air occupies space option b. air has definite volume
8 c The amount of CO2 is higher
9 a CO2 is more than oxygen
10 c Air occupy full volume
Serial No.
Answers Explanation
1 c Air is necessary for burning of objects
2 c Nitrogen in air not essential for growth of plants
3 b Both the statements are correct
Serial No.
Answers Explanation
1 c The amount of nitrogen is highest
2 d Oxygen in the air is 21%
3 b CO2 amount is very less in air
4 a All noble gases together form 0.94%
1 d Oxygen helps in combustion
2 a It is a greenhouse gas
3 c It is the process of nitrification
4 b Presence of chlorophyll
LEVEL 1 Exercise 6 Single correct objective questions
Exercise 7 Statement Type
Exercise 3 Match the following
Calss VI C3:Water and its properties
© Dr. Ravi’s Educational Research and Development Center 4
Serial No.
Answers Explanation
1 a The one which occupy space and has mass is called matter
2 a That’s why they are called greenhouse gases
3 d It is not a decay process
4 c CO2 is a greenhouse gas
5 b They also cause water pollution
6 a Air consists of different gases
Serial No.
Answers Explanation
1 a, b, d The inhaled air is also not so clean
2 a, b, c We cannot see air
3 d Air has mass we can conclude it
4 a, d Air can be compresses
5 a, b Air has mass and occupy space
6 a, c, d Light is not an important factor
7 a, b, c CO2 used in fizzy drinks
Serial No.
Answers Explanation
1 c We cannot increase the level of water
2 b We cannot changed the volume
3 a 40 water is there
4 c When water cooled, it never changes to oxygen
5 d We can carry more air
6 C Total amount of water 1000, container volume 3000 that means air is 2000, take 500 water, increase the amount of air
7 c Plants need CO2 to make food
LEVEL 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 4 ELEMENTS,
COMPOUNDS AND MIXTURES
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 c Sulphur is a polyatomic element
2 a All others are diatomic elements
3 d They are less reactive
4 c Graphite is an allotrope of carbon
5 c Total 114 elements identified
6 c Mercury is a liquid metal
Serial No.
Answers Explanations
1 a Soil is a solid
2 c it is the weight of hydrogen and oxygen
3 b Bi means two
4 a Neutral charge
5 a Covalent compound
Serial No.
Answers Explanations
1 d Nitrogen and oxygen are 2 main gases
2 a Water with CO2
3 b We are using turpentine
4 a Example all solutions
5 d Copper and tin
6 a Water is a compound
Serial No.
Answers Explanations
1 c It is a charged particle
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
LEVEL 1 Exercise 1 Single correct objective questions
Class VI C4:Elements, Compounds & Mixtures
© Dr. Ravi’s Educational Research and Development Center 2
2 a CO2 is a gas with different property
3 d Total 114 elements
4 a Mercury is the liquid metal
5 b Tin-Sn, mercury- Hg
6 a Only atoms exits independently
7 b It has the same property-example solution
8 d All solutions are homogenous
9 a,d He is a monoatomic
10 a Sodium is diatomic
Serial No.
Answers Explanations
1 c metals are good conductors
2 b Metalloids show the property of both metals and non-metals
3 d Statement 1 is false
4 Question not correct
Serial No.
Answers Explanations
1 d Boron is a semi-metal
2 c Helium is a noble gas
3 b Graphite is a non-metal
4 a Sodium is a metal
1 c Silver contain one atom
2 d Oxygen is a diatomic
3 a Sulphur is a polyatomic
4 b Ozone contain three atoms
Serial No.
Answers Explanations
1 a, b, c, d All statements are true
2 a, b, c, d Metals have high boiling and melting point
3 a, b, c, d All are metals
4 a, b, c, d All elements atomicity are same
5 a Only oxygen have same type of atom
6 c This method used to split oxygen and hydrogen
Exercise 2 Statement Type
Exercise 3 Match the following
Exercise 4 One or more than one correct options
Class VI C4:Elements, Compounds & Mixtures
© Dr. Ravi’s Educational Research and Development Center 3
7 a, c AlCl is not a compound
8 b It is the molecule of the compound
9 b It contain two kinds of atoms
10 a, b, d Graphite is a non-metal
11 a 7 elements occur as metalloids
12 a, b, c,d These are the three classifications
13 d Others are having more than one type of atom
14 c Oxygen, nitrogen are examples
15 d Air contain many gases
16 a,b, c,d They have one definite ratio
17 a Water and CO2mixed to form soda water
18 a It contains acetic acid
Serial No.
Answers Explanations
1 b We can make any shape from metals
2 c Mercury and Gallium are liquid metals at 30oc
3 b Both statements are true
4 a
5 b Compound of metal with sulphur is metal sulphides
6 c Pure water is not a mixture
7 b
8 c 8 metalloids exist in periodic table
Serial No.
Answers Explanations
1 d They are poor conductors of electricity
2 a Form of carbon
3 d These all gases are colourless
4 d These gases are non-metals
5 d Noble gases
6 c oxygen is most abundant= 46.6%
7 d Coal is not a compound
8 b Both are solids
9 b This is heterogeneous mixture
10 a Lime water is calcium carbonate
11 c It is a mixture of gold and mercury
12 d All are pure
13 d All these are the characters of elements
LEVEL 2 Exercise 5 Assertion and reason
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Class VI C4:Elements, Compounds & Mixtures
© Dr. Ravi’s Educational Research and Development Center 4
14 a Mixture of two substance
15 d Particle are atom or molecules
16 c Iron is a metal
17 c Oxygen is a non-metal
18 b It is the chemical combination
19 b Carbon found in these
20 a Elements we can’t separate
21 d All these are alloys
22 b Water is a compound
23 b CO2 is a compound
24 c Two or more atoms are present
25 a This is element
26 a Potassium and sodium are highly reactive
27 c These are precious metals
Propel Academy
CHAPTER 5 SORTING AND SEPARATION
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 b Centrifugation apply for colloidal particles
2 d All we can used to separate
3 a Centrifugation apply for colloidal particles
4 c Boiling point is less
5 d Water is volatile liquid
Serial No.
Answers Explanations
1 d Chromatography used to separate colours
2 b Water is the heavier than benzene
3 a Chloroform is heavier than water
4 d Chromatography used to separate colours
5 a Filter paper is used in chromatography
Serial No.
Answers Explanations
1 c one of the components of the mixture sublimes on heating
2 b light weight constituents is blown away by air
3 c These are big one, we can pick it easily
4 c Beads we can pick with hands
5 b Decantation not disturbing the sediments
6 c filtration is used to separate undissolved particles
7 b Ammonium chloride is a sublimate
8 b Common salt and water separated by this technique
9 a Chalk and water is an example
10 d Distillation make pure water
11 c Acetone dissolves nail polish
12 c We are using porous material for filtration
13 c Sedimented material is called residue
Introductory Exercise 1
Introductory Exercise 2
LEVEL 1 Exercise 1 Single correct objective questions
Class VI C5: Separation of Substances
© Dr. Ravi’s Educational Research and Development Center 2
14 b Chloroform easily evaporated
15 c Non-volatile solid
16 d Water will evaporate
Serial No.
Answers Explanations
1 d Chromatography is used to separate amino acids
2 d Evaporation is not suitable for all the solid liquid mixtures
3 b Dry ice is sublimable solid
1 d Separating chalk and water with filtration method
2 c Ethyl alcohol evaporate easily
3 a Iodine is the sublime
4 b We can separate cream from milk by centrifugation
1 a Paint dissolved in turpentine
2 c Iodine is dissolved in benzene
3 b Oil easily dissolved in gasoline
4 d Acetone dissolves nail polish
1 d grain was separated by hand
2 d Both are solids so we can’t separate by sedimentation
3 b Sand and salt can be separated by this method
4 a The method of separation of mixtures where one of the components is magnetic in nature
5 a So we can easily separate them
6 b Chalk and water separate by filtration
7 c Chromatography used to separate colours
1 d Remove waste material and obtain pure materials
2 a, d We can separate blood constituents
3 a, b,c, d Cobalt is a magnetic substance
Exercise 2 Statement Type
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
Class VI C5: Separation of Substances
© Dr. Ravi’s Educational Research and Development Center 3
4 a, b, c, d
All these depends upon separation
5 a Sublime means solid to gas
6 a Simple distillation
7 b Filter paper is used in filtration
8 c We can make chromatograph
9 a, c Sand and saw dust separated by using gravity
10 b Iodine is a sublime
11 a Sand is heavier
12 b If paper using. That is paper chromatography
13 b Water is a universalsolvent
14 C It is a water condensor
15 d Iron is a magnetic substance
1 c Sugar water pass through filter paper
2 b First separate sand water by filtration
3 c Separating funnel
4 d These are inert gases
5 a It is a liquid metal
6 a, d Salt mixed with sand separated by filtration
7 b Both these processes we can see
8 d Camphor is a sublime
9 b Through this method we can separate alcohol and water
10 b Chromatography used to separate colours
11 a Properties are totally different
12 a It is called decantation
13 d Mixture contains all
14 c These are separated by distillation
15 c Ammonium chloride is a sublime
16 a Fractional distillation separate components of petroleum
17 b Higher evaporate slowly
18 c Solid-liquid heterogeneous mixture
19 a Used to separate cream from milk
20 a, d Water only pass through filter paper
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 1 INTRODUCTION TO CHEMISTRY
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d Electrons are orbiting outside the nucleus
2 b Hydrogen contain least number of protons
3 d Lithium contains all three particles
4 d Hydrogen is lighter because it contains 1 protons
5 b Electron has negligible mass
6 a Because they have opposite charges
7 c Because neutron has no charge
Serial No.
Answers Explanations
1 d Al is the correct symbol
2 a B is Boron
3 c Ag is silver
4 d S is for sulphur
5 c Ferrum is a Greek word used for iron
6 c Cupperum is the word used for copper
7 b Cl is used for Chlorine
8 a Ag is for silver
9 a It is coming from a word Plumbum
10 c Hydrargyrum is the name for mercury
1 2 The number of electrons in an orbit is equal to 2n2
2 8 The number of electrons in an orbit is equal to 2n2
3 18 The number of electrons in an orbit is equal to 2n2
4 Orbit Electrons are moving through orbit
5 Two Magnesium has 2 valence electrons
6 Three Boron has 3 valence electrons
7 Two Boron has 5 electrons. 2 will be present on the inner shell to complete duplet
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
Class VII C1:Introduction to Chemistry
© Dr. Ravi’s Educational Research and Development Center 2
8 Two Beryllium has 2 core electrons
9 Zero Every atom except hydrogen has core-level electrons
10 One Li and K have one valence electron each.
1 True Oxygen has 2 atoms
2 True The formula is O3
3 True Oxygen has eight electrons, two in the first shell and six in the outer shell, giving it a valency of two
4 True Sodium has 1 valence election
5 True sulfur atoms form cyclic octatomic molecules with chemical formula S8
6 False If an atom gains electrons, it has a net negative charge and is known as an anion
7 False If an atom gains electrons, it has a net negative charge and is known as an anion
8 True Anionic radius is larger than that of parent atom
9 True O2 is actually smaller in size
Serial No.
Answers Explanations
1 a Atomic mass is high in magnesium
2 d Helium contain very less number of neutrons
3 b Radius of nucleus is smaller
4 d Compounds can be separated by chemical means
5 c Compounds can be separated by chemical means
6 c It becomes the size of a cricket ball
7 a 1015 time taken by hydrogen atom
8 b Sodium fluoride is a compound we can separate by chemical means
9 c Compound contains 2 or more number of atoms
10 d carbon is a non-metal because in elemental form it doesn't form a metallic bond and conduct electricity
Serial No.
Answers Explanations
1 b Same charges repel
2 d Mixtures are not physical combination of two or more elements
Introductory Exercise 4
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Statement Type
Class VII C1:Introduction to Chemistry
© Dr. Ravi’s Educational Research and Development Center 3
3 d Elements need not be pure substances
4 c 114 elements known in the periodic table
Serial No.
Answers Explanations
1 a Electronic configuration of Na is 2, 8, 1
2 c Electronic configuration of Mg is 2, 8, 2
3 d Electronic configuration of Li 2, 1
4 b Electronic configuration of Cl 2, 8, 7
1 b Mass number of Helium 4
2 c Mass number of Boron 11
3 a Mass number of Nitrogen 14
4 d Mass number of Oxygen 16
Serial No.
Answers Explanations
1 d Mendeleev Organized His Table According to Chemical Behavior By 1869
2 b Iodine symbol is I
3 d Mass of an atom depends on mass of protons and mass of neutrons
4 c Mass of a Proton is 1.675 × 10-27 kg.
5 a Positive and negative combine to give zero
Serial No.
Answers Explanations
1 a Atom is the smallest particle
2 a, b P for Phosphorus and K for Potassium
3 c, d Lead symbol Pb
4 a, c These are in continuous motion and vibrating
5 a These are also continuely moving
6 a, c These two contain only one type of atom
7 b Molecule has all properties
8 a, b, c Water is a compound and air is a mixture
9 c Elemental phosphorous is often written as P4
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and Reason
Exercise 5 One or more than one correct option
Class VII C1:Introduction to Chemistry
© Dr. Ravi’s Educational Research and Development Center 4
10 a All others are monoatomic or diatomic
Serial No.
Answers Explanations
1 b Aluminium foil contains only aluminium
2 b This contain different compounds
3 b We can’t separate compounds by physical means
4 a Li is heavier ion
5 c O3 is the chemical symbol of ozone
6 b Hydrogen is diatomic
7 d 9, 10, 10 numbers are present
8 d Nucleus contain protons and neutrons
9 d It will not emit any energy
10 c 18+20=38 and add 2
11 d HCl has more atomic weight
12 b Air is a mixture, and salt water is a compound
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 2 PHYSICAL AND
CHEMICAL CHANGES
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d Swing movement is a periodic change
2 d All these changes we can reverse
3 a We can’t make egg from omelet
4 a It can directly change to gas state
5 c Freezing point
6 a Camphor change from solid to gas
7 a Heat will be released when solid becomes liquid
8 b Camphor is a sublimate
9 d
10 c Heat will be released
11 a Physical changes are reversed
12 a,b,c
13 a Mass will not change
Serial No.
Answers Explanations
1 b Exothermic means they produce heat
2 a It mixes with oxygen to form magnesium oxide
3 d They prepare entirely different substance
4 d Mercury and oxygen formed
5 b Because it produce heat
6 d CO2 and steam produced in candle wax burning
7 c Heat absorbed or generated
Introductory Exercise 1
Introductory Exercise 2
LEVEL 1 Exercise 1 Single correct objective questions
Serial No.
Answers Explanations
1 d We change the iron into old form
2 b We can’t make the milk again from curd
3 a From water vapour we can make water again
4 b This one also reversible change
Class VII C2: Changes around us
© Dr. Ravi’s Educational Research and Development Center 2
Serial No.
Answers Explanations
1 c Milk changing to curd is not reversible
2 c Water changing to ice is not a fast change
3 Question not correct
4 Question not correct
Serial No.
Answers Explanations
1 c Bursting of balloon is a fast change
2 d We can change the reaction
3 b That change we can’t reversed
4 a Plants growing is very slow change
1 d Ice changes into water
2 a Salt formed from salt solution
3 b Solid changes to liquid on heating
4 c Water change to water vapour
Serial No.
Answers Explanations
1 Question not correct
2 d Splitting of water is a chemical change
3 c Water changes into steam is a physical change
5 d Ice and rubber band both are reversible
6 b Wax can be again make into candle
7 b We can’t make the milk again from curd
8 c There is not an exact period for this change
9 d All the statements are true
10 a It is a chemical change
11 b Colour only changes
12 c Energy released or absorbed
13 b We convert the changes
14 c It is a chemical change
15 c We can’t make them again
16 d We will get the same amount of wax
Exercise 2 Statement Type
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and Reason
Class VII C2: Changes around us
© Dr. Ravi’s Educational Research and Development Center 3
4 b Both are correct, and the change is permanent
5 b The product and reactants are same amount
6 a It’s a chemical change we can’t reverse
7 a It’s a chemical change we can’t reverse
8 d It is a very slow change
9 a Because we need fruits to eat
10 a Swing moves a certain interval of time
Serial No.
Answers Explanations
1 b, d Respiration is chemical change
2 a, b , c,d All these changes we can change
3 a, d All these statements are true
4 a, b, c All these are physical changes
5 a, b, d These two changes are chemical changes
6 a, c, d Clock pendulum also a periodic change
7 a, b, c, d All these changes are non-periodic
8 a, c Melting of wax only reversible
9 a, b, c, d All these are fast changes
10 c, d Burning of paper is an irreversible change
11 b, c, d These can be reversed
Serial No.
Answers Explanations
1 a It is a physical change, no new substances formed
2 b That one also a chemical change
3 No answer
Souring of milk is a not a reversible change
4 d Both are chemical change
5 c Both physical and chemical changes occurs
6 c Example. Burning of candle
7 d Sugar burning is a permanent change
8 b We can see the change
9 A,b,c That one only we can change
10 d Digestion is a chemical change
11 d All these are physical changes
12 a Photosynthesis is a chemical change
13 b Mixing means physical changes only
14 b If we convert milk into curd, it’s an irreversible change
Exercise 5 One or more than one correct option
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Class VII C2: Changes around us
© Dr. Ravi’s Educational Research and Development Center 4
15 c It is a slow change
16 d Occur within a minute means very fast change
17 c It is a physical change
18 d All these can be reversed
19 a, d Germination is a slow change
20 a Physical change only
Propel Academy
CHAPTER 3
AIR AND WATER
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 a Air contain 78% of nitrogen
2 d Krypton and xenon are 2 more inert gas is there
3 a CO2 changes he colour of the lime water
4 c Coal is a solid fuel
5 d Because air is a matter
6 d Air contain different gases
Serial No.
Answers Explanations
1 c Filling tyres
2 d Moving air is called wind
3 c Molecular weight 18
4 a Ice melted to form water
5 d Camphor is an example
6 b Steam changes to water
Serial No.
Answers Explanations
1 b Melted ice has smaller volume
2 d They make sticky scum
3 d Sulphates and chlorides
4 d carbonates cause hardness
5 a Two main gases are nitrogen and oxygen
6 d Ratio of oxygen and nitrogen is 1:4
7 a Humidity more there
8 c Solid to liquid by melting
9 d Water vapour condenses to form clouds
10 c Y contain more water and temperature
11 c Water evaporated to form water vapour
12 b They assume the shape of the vessel
13 c These 2 process used to remove hardness
Introductory Exercise 1
Introductory Exercise 2
LEVEL 1 Exercise 1 Single correct objective questions
Class VII C3: Air & Water
© Dr. Ravi’s Educational Research and Development Center 2
14 d When a drop of water is poured over anhydrous copper sulphate (white), it turns to blue colour, due to formation of hydrated copper sulphate
15 b Decrease the heat from 80
16 b Hydrogen and oxygen are the 2 components of water
17 b Air contain a lot of gases
18 a Oxygen is involved
19 c Hydrogen is very less in air
20 a The main gases are nitrogen and oxygen
21 b The clouds condense and form rain
22 a Steam condenses to form water
Serial No.
Answers Explanations
1 b Chlorides cause permanent hardness
2 Question not correct
3 b Pure water has pH 7
Serial No.
Answers Explanations
1 d The amount of nitrogen is 78%
2 a Oxygen present in the air is 20 %
3 b CO2 amount is .38%
4 c The amount of argon is .93%
1 c Permutit is also known as zeolite
2 d Anhydrous copper sulphate is used for water test
3 a Temporary hardness by calcium hydrogen carbonate
4 b Permanent hardness caused by CaCl2
Serial No.
Answers Explanations
1 d Permanent hardness caused by CaCl2
Exercise 2 Statement Type
Exercise 3 Match the following
LEVEL 2 Exercise 4 Assertion and Reason
Class VII C3: Air & Water
© Dr. Ravi’s Educational Research and Development Center 3
2 b Water is hydrogen and oxygen
3 a Water is a compound
4 b Air is a colorless gaseous substance
5 a Mountaineers need oxygen at heights
6 d Due to pollution, temp is high in cities
7 b Air is polluted due to firewood gases
Serial No.
Answers Explanations
1 b, c Melting means solid to liquid
2 a, b, d Air is a matter and mixture
3 a, c Parachute fly using air
4 d Sodium permutit is zeolite
5 a, b, c, d It is not good for washing
6 a, c
7 b, c If we tilt the cup, water enter
8 b Water has no definite shape
9 a, c, d The frog is not getting enough food and air
10 d Air can be compressed easily
Serial No.
Answers Explanations
1 c Solid to liquid
2 b Temperature affects the state of water
3 b It is actually a matter
4 c Fizzy drinks we are using CO2
5 d Exhaled air contain water vapour
6 c Water vapor coming from air
7 d Compressed air means it increase the volume
8 a Water reaching to rivers in the same form
9 c The air can be compressed
10 a Ice water is there, so air become cooler
Exercise 5 One or more than one correct option
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 4
CHEMICAL BONDING
Chemistry
Introductory exercise no 1
Serial No.
Answers Explanations
1 a Electrons are in the orbits in an atom
2 b Noble gases are mono-atomic in nature
3 d All these are noble gases
4 c Neutral charge
5 c It has 2 electrons
Introductory exercise no 2
Serial No.
Answers Explanations
1 a Covalent means sharing
2 d They are more stable
3 b Covalent means sharing electrons
4 a They give electron and become negative
5 b 2 like atoms called non-polar bond
6 b Ionic compounds are soluble
Introductory exercise no 3
Serial No.
Answers Explanations
1 a Intramolecule means inside the molecule
2 d Both O and F are electronegative
3 c They have low melting and boiling point
4 a In sulphur we can see the first type
5 a These are bad conductors
6 b Intra within one
Single answer questions
Serial No.
Answers Explanations
1 b Chemical bond means the attraction and repulsion at particular distance
2 a Helium has two electrons in the outer shell
3 c Having eight electrons total ensures that the atom is stable
4 d All these help the atom to attain stability
5 c Both parent and its ion
6 b 2, 8 is the electronic configuration
7 b Fused one only conduct electricity
8 a They lose electrons and oxidized
9 b They held together by electrostatic force
10 c 3 electrons transfer from AlN
11 c 35 is the atomic number of that atom because it has valency 1
12 a High electro negativity
13 b Aluminium oxide is amphoteric
14 d Water decreases the inter ionic attraction
15 c Both ions are present
16 c It is possible between two similar and dissimilar atoms
17 b Sharing of electrons
18 d There is no free ions and no free electrons in covalent compounds
19 a Covalent means sharing of electrons
20 b Be has the tendency to form covalent bond
21 b Covalent bond formed
22 c 50 electrons are present
23 b The atomic number is 16
Statement Type
Match the following
Serial No.
Answers Explanations
1 c Covalent bond is formed between two similar atoms
2 d Nucleus contains only protons and neutrons
3 Question not correct
4 d Covalent bonds are weaker than ionic, so they have low melting point
Serial No.
Answers Explanations
1 a Sulphur is a covalent compound
2 d Chlorine has single bond
3 b Nitrogen has triple bond
4 c Oxygen has double bond
One or more than one answer
Assertion and reasoning
Serial No.
Answers Explanations
1 d Covalent bond present in this molecule
2 a It is a stable atom
3 c Covalent is the sharing of electron
4 b Calcium chloride is ionic compound
5 c They may exist solid, liquid or gas
Questions from Olympiad
Serial No.
Answers Explanations
1 b Pure covalent bonding is only found in elements
2 b Argon is the nearest noble gas
3 c They form covalent bond
4 b It is the other name of ionic bond
5 b Transfer of electrons
6 d All these form covalent bond
7 d Covalent solid having metallic lustre
1 c Sodium valency 1
2 d Aluminium had valency 3
3 a Carbon has a valency of 4
4 b Sulphur has valency 2
Serial No.
Answers Explanations
1 a, b, c, d They can lose or gain maximum 4 number
2 a They are hard solids
3 b, c, d Hydrogen form hydrogen bond
4 b, c, d These three exhibit octet rule
5 d They don’t undergo chemical reaction quickly
6 a, b, c Ionic compounds are bad conductors
7 b Graphite is a good conductor of electricity
8 d All these form single bonds
9 a, b, c, d All these are the properties
8 b Electrostatic force can be seen
9 b Covalent compounds are soluble in non polar solvents
10 b Octet rule explained this theory
11 a Valence electrons participate in bond formation
12 b 5 is the number of electrons in that atom
13 d Repulsion and attraction equal
14 b Be least electronegative
15 a Energy decreases
16 c The higher the bond energy, the shorter the bond length
17 a The force of attraction that holds the atoms is chemical bond
18 c H-F has strong bond
19 b H and CL, F or Br form polar bond
20 a All others form hydrogen bond
21 b NO3 having covalent bond
22 c Polar covalent bond present in water
Propel Academy
CHAPTER 5 ACIDS, BASES
AND SALTS Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 b Tartaric acid present in tamarind
2 a Bases have bitter taste
3 c Curd taste is sour because of lactic acid
4 a Latin, acidus means sour
5 c Salt and water produced
6 b Ants contain formic acid
7 a Grapes also contain tartaric acid
Serial No.
Answers Explanations
1 a Its acidic in character
2 b Acidic oxides are formed when non-metals react with oxygen
3 a Acid changes the colour from blue to red
4 c That contains at least one oxygen atom and one other element
5 d Bases and acids only form salts
6 c All neutral oxides are gases
7 a Calcium oxide is a basic oxide
8 d They can react with acids and bases
9 a CO2 is an acidic oxide
10 a They are solid in nature
Serial No.
Answers Explanations
1 d Boric acid used all these
2 a It is the mixture of concentrated HCl and nitric acid
3 d They are used as industrial agent
4 d It is used in explosives
5 b Salt and hydrogen gas
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
Class VII C5: Acids, Bases & Salts
© Dr. Ravi’s Educational Research and Development Center 2
Serial No.
Answers Explanations
1 d a crystalline salt having the composition of a mixture of two simple salts
2 c These two are Efflorescent Salts
3 d All these are deliquescent substances
4 a Calcium oxide and H2SO4 are hygroscopic
5 d Formula is C2H2O4
6 b Tomatoes contain oxalic acid
7 c H for hydrogen and Cl for chlorine
8 a Phosphoric used in anti-corrosive paints
9 a Litmus made from lichens
10 b If we mix yellow and whit clour base, it will get red colour
11 a HCl is present in our stomach that is help in digestion
12 d Lemon and orange contain citric acid
13 c Above 7 means it is basic in nature
Serial No.
Answers Explanations
1 b Litmus paper is commonly used as indicator
2 c pH scale works for acidic and basic solutions
3 Question not correct
4 c Basic solutions contain OH- ions
5 c pH of blood is slightly basic in nature
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Statement Type
Exercise 3 Match the following
Serial No.
Answers Explanations
1 d Lactic acid present in curd
2 c Vinegar contains acetic acid
3 b Citric acid present in lemon
4 a Oxalic acid present in tomato
1 d Sulfuric acid was called "oil of vitriol”
2 c It was historically called muriatic acid as it produced from rock salt
3 b Magnesium hydroxide is known as milk of magnesia
4 a Calcium hydroxide is quick lime
Class VII C5: Acids, Bases & Salts
© Dr. Ravi’s Educational Research and Development Center 3
Serial No.
Answers Explanations
1 c, d KOH is a strong base and HCl is a strong acid
2 b Less than 7 are acidic
3 b That is why it become more acidic
4 a That is efflorescence
5 c Antacid used for indigestion
6 a Acid gives H+ ions in water
7 b Acids cause tooth decay
8 d That means it is basic
9 b More pH value means more acidic
10 b Base gives OH- in water
11 a, b NaCl is a salt
12 b, d These are acid and salt respectively
13 b Soap contain NaOH
14 a Less than 7 means acidic
15 a Very strong acid and base
16 a Acid gives red colour
17 a,c Tap water pH ranges from 6.5 to 8.5
Serial No.
Answers Explanations
1 b It is a weak acid
LEVEL 2 Exercise 4 Assertion and Reason
Serial No.
Answers Explanations
1 d Carbonic acid is an acid
2 b These are the property of bases
3 b Litmus shows different colours
4 c Calcium hypochlorite used for making bleaching powder
5 d All neutral oxides are gases
6 b All acidic oxides are gases
7 d Phosphoric acid used for rust removal
8 b Above 7 means it is basic in nature
9 a So they are hydrated salts
Exercise 5 One or more than one correct option
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Class VII C5: Acids, Bases & Salts
© Dr. Ravi’s Educational Research and Development Center 4
2 b Tooth paste are basic in nature
3 a Means acidic in nature
4 c We can dilute acid by adding water
5 b More ions present
6 a Means acidic
7 b Presence of CO2 in the air
8 d Borax is a base
9 d NaOH is soluble in water
10 b Base change red to blue
11 b Indigestion due to acidity
12 a Ants contain formic acid
13 a Most waste are acids
14 c Normally ants contain this acid
15 d KOH is a base
16 b They gave electrons
17 a Litmus paper is most commonly used
18 a Hydrogen present in all acids
Propel Academy
CHAPTER 1 METALS AND NON-METALS
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d Elements any be metals, non-metals and metalloids
2 c Elements classified on chemical and physical properties
3 b These two are liquid metals
4 c Luster property shows their shininess
5 a Malleable property make them into thin sheets
6 b Silver has ductile property
7 c They can conduct electricity
8 d Iridium has highest density
9 c Iron has highest boiling point
1 b If it lose electron, it become positive
2 d All have high electropositive character
3 b Valence electrons present in the outermost orbit
4 c Then they become electro negative
5 d Zinc has less electro negativity
6 b Basic oxides are basic in nature
7 c Aluminium is a strong reducing agent
8 d They can appear in any of these state
9 a Gold and silver have luster property
10 b Diamond is the hardest substance
11 d Diamond is the hardest substance
12 b Non-metals are bad conductors
13 a Non-metals have less density
1 a Metals can be drawn into wires
2 a Metallic bonds are seen in metals
3 a Metals like Aluminium acts as reducing agent
4 c Borax made from Boron
5 b It is made from Zinc not from iron
6 d Copper is not used for fireworks
Introductory exercise 1
Introductory exercise 2
Introductory exercise 3
Class VIII C1: Metals & Non-metals
© Dr. Ravi’s Educational Research and Development Center 2
7 a They react with alkali
8 c Beaching powder made from chlorine
9 a They produced from magnesium
10 b Sulphur used in vulcanization
1 c They show the characters of metals and non-metals
2 a They are looking like metals
3 c Phosphorous is not a metalloid
4 b Metalloids are ductile
5 c Their characters between metals and non-metals
6 b Metalloids are semi-conductors
7 c It used to increase
8 b Tellurium used to give colour for vases
1 b Non-metals are chemically inactive
2 d Silicon is not a noble metal
3 b Silver has some antibacterial properties
4 c These are resistant to corrosion and oxidation
5 b 24 carrot means pure gold
6 c 58.5% gold present
7 d Copper and silver mixed with gold
8 a 750 parts of gold per 1000
1 c Graphite is good conductor
2 c Metals form acidic oxides
3 a, b , d These all are the properties of metal
4 d They are forming acidic oxides
5 a Aluminium has this property
6 c Sodium is a metal
7 d Nitrogen is a non-metal
8 b Graphite has not such kind of property
9 a Iron is a good conductor
10 c Silver has that property
11 b Metals can make sound also
12 a Alnico is the alloy of Aluminium and Nickel
Introductory exercise 4
Introductory exercise 5
LEVEL 1 Exercise 1 Single correct objective questions
Class VIII C1: Metals & Non-metals
© Dr. Ravi’s Educational Research and Development Center 3
13 b That is Copper sulphate
14 b It is the homogenous mixture
15 b Alloy is homogenous mixture of two or more elements in a definite proportion
16 c Antimony is a metalloid
1 c Symbol of Rubidium Rb
2 a Symbol of Palladium Pd
3 d Symbol of Molybdenum Mo
4 b Symbol of Radium Ra
1 c It is a carbonate ore of Mg
2 d It is an oxide ore of Aluminium
3 b It is a halide ore of Na
4 a Gypsum is a sulphate ore of Ca
1 c Non-metals are generally brittle
2 b It is a good conductor also
3 a That’s why we are writing like this
4 b Sodium can be cut with a knife
5 d The non metal used to make dry cells is graphite
6 b Gangue contains impurities
7 b Mineral + Gangue = ore
Exercise 2 Matrix Type
LEVEL 2 Exercise 3 Assertion and reason
Exercise 4 One or more than one correct options
1 c, d Sodium is very soft
2 a, b Neutralization reaction
3 c It is not releasing hydrogen
4 a, b, c Sulphur is brittle
5 b Platinum is a noble metal
6 b 4 to 8 electrons are present in outermost shell
7 b Valency of SO3 is 6
8 b Non metals form covalent bond with other non metals
9 c Oxy acids are formed
10 a, d Non metals have high electro negativity and low electro positivity
Class VIII C1: Metals & Non-metals
© Dr. Ravi’s Educational Research and Development Center 4
11 b Non metals tensile strength is low
12 d Alloying is done to increase overall properties
13 d Non-metals are not reacting with water
14 b Under high temperature non metals reacting with metals to form oxides
15 a Oxides of carbon are acidic in nature
16 a, b, c Coinage metals are copper, gold and zinc
1 c Liquid metal is mercury
2 a Sodium can be cut with knife
3 a Metals are good conductors of heat and electricity
4 a Mercury is poor conductor of electricity
Exercise 5 Paragraph Type Questions
Level 3 Exercise 6 Questions from/for Olympiads
1 b Bauxite is an ore of aluminium
2 Pic is not there
3 a Galvanization is the process
4 c One and three is not feasible
5 c Magnentite is a carbonate ore of Mg
6 b Others are metals
7 c 93% of iron is present
8 a All ores are minerals
9 c Those elements are reactive
10 a H2 gas is evolved
11 b This is based on their reactivity strength
12 b Nickel is used for making boats
13 b Salt and water formed in this reaction
14 c Metals react with oxygen to form metal oxide
15 b Non metals applied on wounds
16 d Phosphorus is highly reactive
17 a Sulphur is used in vulcanization of rubber
18 c Aqua regia is 1 part HNO3+ 3 parts conc HCl
19 b Red colour of ruby is due to chromium oxide
20 b Nickel is used in preparation of vanspathi
Propel Academy
CHAPTER 2 COAL AND
PETROLEUM Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d Solid, gas and liquid fuels are available
2 c It never be poisonous
3 d We are using fuels for cooking
4 a We will get it continually
5 c Coal is a non-renewable source
6 a Coal formed from plants
7 d It consists of C, H and O
8 a Coal formed due to high temperature and pressure
9 c The process of conversion of vegetable matter called carbonization
10 a Coal used in thermal power station
11 b Coal formation is called carbonisation
1 b The process of destructive distillation of coal is carried out by heating coal at a high temperature
2 c This process is also called as pyrolysis
3 c Plastic is not formed in this process
4 b This is normally used for the preparation of paints
5 a Liquor means liquid or fluid
Introductory exercise 1
Introductory exercise 2
1 b Lignite is the lowest grade
2 d Highest amount of carbon in anthracite
3 c Natural gas obtained from this process
4 c Bituminous is a soft coal
5 d It has highest quality
6 b This type coal has shininess
7 c Nitrogen is not present in coal
8 d It has superior quality
Introductory exercise 3
Class VIII C2: Coal & Petroleum
© Dr. Ravi’s Educational Research and Development Center 2
6 d Coal tar not used for making coke
7 a It used as good reducing agent in the manufacturing of steel.
8 c Both gases are produced
9 d It is a mixture of hydrogen, methane and carbon monoxide
1 b The world's oldest running oil refinery, located in the northeast corner of India
2 b It is house hold variety
3 a Natural gas is an ideal fuel
4 d All these are ideal fuels
5 c Fuel means coal only we are using in nuclear power plant
6 a CO entered into our blood and bind with hemoglobin
7 a Biogas is a mixture of methane and CO2
8 c Coal is obtained from waste plant materials
9 d Crude oil contains all these
10 a That’s combustion
11 b LPG is not in the manufacture of chemical fertilizers
12 d Diesel has high volatility
Introductory exercise 4
1 b The unrefined form of petroleum is called crude oil or rock oil
2 c Petroleum was formed from the organisms living in the sea
3 a By drilling in the Earth’s crust and sinking pipes deep down in the rocks
4 b The process of separating the various components of petroleum from one another is known as the refining of petroleum
5 a Fractional distillation is a method
6 a 150-2500c kerosene obtained
7 b The residues are formed in 3500c
8 a Fractional distillation, crude oil heated in 4000c
9 c Kerosene used in jet
10 a In petrol, number of carbon atoms low
Introductory exercise 5
1 b Main constituent of natural gas methane
2 a It has a very high calorific value 50,000 kJ/kg
3 c Compressed natural gas
4 d Grass is not related with fuels
5 a Gas changes to liquid form
LEVEL 1 Exercise 1 Single correct objective questions
Class VIII C2: Coal & Petroleum
© Dr. Ravi’s Educational Research and Development Center 3
13 a Petrochemicals are the products
14 a Petroleum Conservation Research Association
1 b Crude oil is a fossil fuel
2 d Another name of petroleum is hydrocarbons
3 d The most common resources of energy used in automobiles is diesel
4 c Petroleum can be processed by fractional distillation
5 c Solid fuels leave more smoke and ash on burnings
6 c Coal is formed by carbonization
7 a Fuels combine with oxygen to produce heat and light
8 a Main constituent of gobar gas is methane
9 a Gas in lpg cylinders is liquefied by applying high pressure
10 b Coke
11 a,b,d Good fuel should be low cost, minimum pollution and readily available
1 a Petroleum is rock oil
2 b Crude petroleum is heated at 400oc to 500oc
3 c Different boiling points of each fraction
4 d Gasoline is used as fuel
Exercise 2 One or more than one correct answer
Exercise 3 Paragraph questions
LEVEL 2 Exercise 4 Assertion and reason
1 a Coal and petroleum formed naturally
2 a It is used to obtain producer gas (CO + N2) by passing air over the red hot coke
3 b So we can use renewable source
4 d Anthracite is the highest rank coal
5 b Heating coal at 12700c
6 c Reason is false
7 b Natural gas can be stored under high pressure
8 b Methane is separated from hydrocarbons and hence natural gas is refined
Class VIII C2: Coal & Petroleum
© Dr. Ravi’s Educational Research and Development Center 4
Exercise 5 Match the following
1 a It the process related with coal formation
2 b Coke undergo destructive distillation
3 d Hydrocarbons obtained from cracking
4 c Refining is the process related with petroleum
1 d That is liquefied petroleum gas
2 a This type of coal used in paints
3 b Paraffin wax used in ointments
4 c Petrol is an aviation fuel
1 c Petroleum has very strong smell
2 a Natural gas occurs above petroleum oil
3 a It is very valuable oil
4 a These are the main constituents
5 c These days, bitumen, a petroleum product, is used in place of coal-tarfor metalling the roads
6 b, c, d These are not the properties
7 a, d Coal gas contains all these
8 b Electricity produced from tides
9 b, c, d Agricultural wastes are renewable source
10 a,c,d Ideal fuel cause minimum pollution
11 a Coal is a solid fuel
12 d Diamond occurs naturally
13 a Coal gas is not obtained
14 c LPG leakage is detected by ethyl mercaptan
15 b
16 b Methane is known as fire damp
Level 3 Exercise 6 Questions from/for Olympiads
Propel Academy
CHAPTER 3 ATOMIC AND
MOLECULAR MASS
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 a This is avagadro’s number
2 c Mole is the unit of measurement
3 d Isotope is the version of same element
4 d All are carbon isotopes
5 a 28.09 is the atomic mass of Si
6 c Specific heat of water is 1
1 a Half number due to isotope
2 a Relative atomic mass 12 of carbon
3 c Mass % of copper is 0.8882
4 c 3O3 relative atomic mass 180
5 b the ratio of the average mass of one atom of an element to one twelfth of the mass of an atom of carbon-12
6 c Molecular mass of Na2CO3. 10 H2O is 286
7 b 100.1151. KHCO3 is a white crystal at room temperature
8 a Molar mass of CaCO3 is 100.0869 g/mol.
9 b ChlorineCl 35.453263.888% CalciumCa 40.078136.112%
10 b 1 g = 1000 mg Molar mass of carbon dioxide (CO2) = 44 g mol-1 Given mass of CO2= 220 mg = 0 22 g Number of moles , 0.22/0.44=0.005
11 c Mass ratio C : H = 82.66 : 17.34 Divide by relative atomic masses to get the mole ratio Mole ratio C : H = 82.66/12.01 : 17.34/1.008 = 6.88 : 17.20 To get this as a 1:x ratio, divide both by the smaller of the two Mole ratio C : H = 6.88/6.88 : 17.20/6.88 = 1 : 2.5 To get this as a whole number ratio, multiply both by 2
Introductory exercise 1
Introductory exercise 2
1 a Molar mass of oxygen is 32
2 d It contain iron and oxygen
3 c Atomic mass of oxygen 16
4 b NaCl formula mass 58.5
5 a CaCl2 molar mass 110
6 b Mg3N2 is the formula
7 c 22.4 L is the molar volme of ideal gas
LEVEL 1 Exercise 1 Single correct objective questions
Class VIII C3:Atomic & molecular mass
© Dr. Ravi’s Educational Research and Development Center 2
Mole ratio C : H = 2 : 5 Therefore, the empirical formula is C2H5
12 c The correct empirical formula C3H4F2 and then calculated the mass of this empirical formula to be 78 which is of the molecular mass and multiplied the formula by 2
1 d Molar mass of Zn 65.4
2 c Molar mass of water 18
3 a Molar mass of oxygen 32
4 b Molar mass of N2 28
1 d Formula of acetic acid CH3COOH
2 a Formula of ammonia NH3
3 c Formula of methane CH4
4 b Formula of ethane C2H6
1 d HCl – r
2 a H2SO4- p
3 c NH3 – s
4 b HNO3 - q
1 c CaCO3 – s
2 d C – p
3 a NaCl – r
4 b Sucrose – q
1 b H2O molecular mass is 18 u
2 c Molecular mass of C2H5OH= 2(12)+ 5(1)+16+1 = 46 u
1 b 2P + 3Cl2 -- 2PCl3
2 c 1NH3 + 3 Cl2 -- NCl3+ 3HCl
1 b Equations is always a balanced one
2 d Flourine atomic weight 18.9 u
3 b One mole =12g of Carbon
4 d HCl molecular mass is 35.5 u
5 b SI unit of molar mass is kg/mol
6 b Both statements are true
7 b Water is H2O
Exercise 2 Match the following
Exercise 3 Paragraph questions
LEVEL 2 Exercise 4 Assertion and reason
Class VIII C3:Atomic & molecular mass
© Dr. Ravi’s Educational Research and Development Center 3
8 a Aspirin is C9H8O4
9 b NaCl formula mass is 58.44 u
10 b Cholroform is CHCl3
1 c Structure of glucose and benzene are similar
2 d Empirical formula shows the whole number ratio
3 c SO3
4 a C 1.00 , H 2.643 It looks by inspection that multiplying by 3 should give whole numbers: C 3.00 , H 7.93 ~ 8 , Empirical formula is C3H8
5 b Na = 42.07/32 = 1.829 P = 18.89/31 = 0.609 O = 39.04/16 = 2.44 then divide each of you answers by the smallest: Na = 1.829/0.609 = 3 P = 0.609/0.609 = 1 O = 2.44/0.609 = 4 so the empirical formula is Na3PO4
6 b Styrene has 92.26% of Carbon and 7.74% of Hydrogen
7 a 14% hydrogen and 86% carbon
8 c We can’t divide the number of O
9 c Uranium has more than one isotope
10 b Nitrogen is a chemical element with symbol N and atomic number 7
1 b The compound butene has a molecular formula of C4H8
2 Question is incomplete
3 a Used in the study of crystalline solids
4 b 6.022x1023 particles
5 d Molar mass
6 a 6.022x1023 particles= 1 mole
7 b 1 mole = 65.38 g = 6.022 x 1023; 2.5 mole = 2.5 x 65.38 =2.5 x 6.022 x 1023= 1.51 x 1024 atoms
8 d All of the above
9 b Tin has 10 number of isotopes
10 a Relative atomic mass
11 d Atoms
12 c Given amount is 10 moles of water = 10 x 3 = 30 mole of atoms
13 b Coefficient of Hydrogen is 17
14 a 1KNO3 +H2SO4 -- HNO3 + KHSO4
Exercise 5 One or more than one correct options
Level 3 Exercise 6 Questions from/for Olympiads
Propel Academy
CHAPTER 4 CHEMICAL BONDING
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 c 5 valence electrons for nitrogen
2 a Covalent means sharing of electrons
3 a Lewis proposed Lewis dot formula
4 b Ther are 6 evalence electrons
5 c Ionic compounds possess high melting and boiling points
1 b Na has 11 electrons and Na+ has 10 electrons
2 a Valence of ion = no of positive or negative charges acquired by an atom
3 d NaBr is an electrovalent bond
4 a Chemical bond
5 b Cation is formed by losing an electron
6 b Electrostatic forces held cations and anions together
7 a H2 is covalent
8 b Diamond has 3 d covalent structure
9 b Each bond has 2 electrons and hence double bond has 4 electrons
10 c Nitrogen has triple bond between the atoms
11 b CaS has the highest melting point
12 b Potential energy decreases
13 a A covalent bond is formed when combining atoms share the electron pairs
14 c Both attractive and repulsive forces
15 a C2H2 is a covalent compound
16 a Bond formation is always exothermic
17 c It shares electrons
18 b Bond between y atoms is covalent
19 c X2Y is the compound
Introductory exercise 1
Introductory exercise 2
1 d these exist as gases or liquids of low boiling points
2 b Polar covalent bond is a type of covalent bond formed between two non-identical atoms
3 d soluble in non-polar solvents like benzene, carbon tetrachloride, ether
4 b sharing of two electron pairs is called a "double covalent bond
LEVEL 1 Exercise 1 Single correct objective questions
Class VIII C4:Chemical Bonding
© Dr. Ravi’s Educational Research and Development Center 2
20 d Al transfers three electrons to Nitrogen
1 a, b,c,d All can form covalent bond
2 c forming three covalent bonds, a so-called triple bond
3 d An oxygen atom can form two covalent bonds
4 a, b Molecules having single bond are H2, F2, Cl2
1 d It is a weak acid
2 a, c It forms ionic bond
3 a, c It forms covalent bond
4 a, d Na2SO4 is a salt of a strong acid(H2SO4) and strong base(NaOH)
1 a Strong metallic bond
2 b Weak metallic bond
1 b Non mobility of hydrated aluminium and chloride ions
2 a Mobility of hydrated aluminium and chloride ions
1 c Covalent bond sharing electrons
2 b It is made upof ions
3 b A bond formed by the equal contribution and equal sharing of electrons between two atoms or more atoms is known as covalent bond
4 b Elctrons gain substance is electronegative
5 a Nitrogen has 5 valence electrons
1 a,b, c, d by transfer of one or more electrons from one atom to another
2 a, d Argon is a noble gas
3 a, b, c Atoms can gain or lose more than one electron at a time
4 a, b, c, d All these have ionic bond
5 a,c, d covalent bondsseem to be weaker than those with ionic bonds
6 b Graphite is a good conductor
7 d Molecules having single bond are H2, F2, Cl2
8 a, b, c Ionic compounds possess high melting and boiling points
9 c Bonds have both attraction andrepulsion
10 a Helium ; Argon have eight electrons in their valence shells
Exercise 2 Matrix Type
Exercise 3 Paragraph questions
LEVEL 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
Class VIII C4:Chemical Bonding
© Dr. Ravi’s Educational Research and Development Center 3
11 c They want to attain stability
12 d All of these
1 d Noble gases
2 b Force of attraction overcome force of repulsion
3 a Valence electrons in an atom
4 b Valency of nitrogen is 3
5 c Ionic substances are soluble in water
6 a Have similar electronegativity
7 b Covalencies are 1, 1, 2, 3
8 d Maximum no of electrons is BCl3
9 d They undergo chemical reaction quickly
10 d All of these
11 d All of these
12 a,b,c Ionic properties do not exhibit space isomerism
13 c High melting point, high boiling point
14 c Conductors in solid state
15 a Higher the temp, more the solubility
Level 3 Exercise 6 Questions from/for Olympiads
Propel Academy
CHAPTER 5 CARBON AND ITS
COMPOUNDS
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d All these are allotropic forms of carbon
2 d It has no free electrons to conduct electric current
3 a Double bond is formed by the sharing of two pairs of electrons of the valence shell. Example: Oxygen molecule (O = O)
4 c Methane is formed by non-polar covalent bonding, CO2 contains covalent
5 b Carbon dioxide demonstrating adouble bond
6 c Covalent means sharing of electrons
7 d It has no free electrons to conduct electric current
1 a The general formula for an alkane is: CnH2n+2
2 b Alkyne general formula CnH2n-2
3 d German chemist Friedrich Wöhler first synthesized urea in 1828
4 a Minimum 4 carbon atoms
5 c This is the name of ethanol
1 b Power alcohol generally has 80% petrol and 20% ethanol
2 b Less oxygen means less combustion leading to unburnt carbon particles giving utensils black colour at bottom
3 c Rectified spirit is 95% ethanol
4 a or b Ethanol
5 c Acetic acid is the product
6 c Secondary alcohols have an -OH functional group
7 b Six C-H bonds are there
8 d Aall these are properties of carbon
9 a A saturated hydrocarbon (Alkane) would have the general formula CnH(2n+2)
10 c Acyclic or open chain compounds: These contain alkanes, alkenes, alkynes
11 c Phenol, also known as carbolic acid, is an aromatic organic compoundwith the molecular formula C6H5OH
12 a All others have general formula CnH2n+2
Introductory Exercise 1
Introductory Exercise 2
LEVEL 1 Exercise 1 Single correct objective questions
Class VIII C5:Carbon & its compounds
© Dr. Ravi’s Educational Research and Development Center 2
1 d Diamond is abrasive
2 c Water gas is a synthesis gas, containing carbon monoxide and hydrogen
3 b Producer gas, mixture of flammable gases (principally carbon monoxide and hydrogen
4 a Graphite is used as a lubricant
1 b Increased amount cause global warming
2 a It binds with haemoglobin
3 d Natural gas produced from fossil fuels
4 c Dry ice is solid CO2
1 b They contain sulphur and nitrogen
2 c It produces less amount of CO2
1 a Due to excitement and de-excitement of electrons
2 b Due to total internal reflection of light
1 a Carbon has a lot of special properties
2 a Diamonds get their brilliance from three things: reflection, refraction and dispersion
3 a Graphite is another form of carbon
4 b Oxidizing agents give oxygen to another substance
5 c Hydro carbon has only hydrogen and carbon
1 d Have weak forces of attraction between layers
2 b Diamond has an extremely low thermal expansion, is chemically inert with respect to most acids and alkalis
3 a, c it has a formula C2H4 (ethylene) it obviously has a double bond
4 b, c naphthalene is classified as a benzenoid polycyclic aromatic hydrocarbon
5 a, b, c, d
Cellulose, which makes up the walls of plant cells, contains carbon
6 a, b, c All these are properties of carbon
7 a Allotropes are differentstructural forms of the same element
8 a,b, c, d
Carbon nanotubes (CNTs) are allotropes of carbon
9 c,d Isoprene (C5H8)contains two double bonds and is therefore even more reactive
10 c, d Theelectron configuration of a carbon atom is 1s22s22p2
11 a, b, c alcohol is not a hydrocarbon
Exercise 2 Match the following
Exercise 3 Paragraph questions
Level 2 Exercise 4 Assertion and reason
Exercise 5 One or more than one correct options
Class VIII C5:Carbon & its compounds
© Dr. Ravi’s Educational Research and Development Center 3
12 d carbon is also the most important element plastic
13 b, c, d All these are allotropes
14 d Carbon arranged as tetrahedral
15 d All these contain carbon
16 d Dry ice is frozen oxygen gas is wrong statement
1 b The four valence electrons of each carbon atom participate in the formation of very strong covalent bonds
2 b The most reactive form of carbon is charcoal
3 c Electric conductor
4 a CO2 is the option
5 d Lead pencil has graphite
6 a Incomplete combustion gives CO
7 b Carbon dioxide gives tangy taste to soft drinks
8 d Different layers in graphite are held together by vander wals’s forces
9 b,d Main constituent of LPG are propane and butane
10 c Good fuel has high calorific value
11 a Ethane do not contain multiple bonds
12 c Charcoal is the answer
13 d Diamond has no free electrons
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
Propel Academy
CHAPTER 1 WHAT IS INSIDE
THE ATOM
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 b Protons present inside the nucleus
2 a Protons are heavier than electrons
3 b - Particles are made up of two protons and two neutrons and are He nuclei
4 b It is based on atom
5 b This is the mass of proton
6 b He used gold foil for his experiment
7 b Hydrogen represents proton
1 b Electron Capacity = 2n2
2 c It is the diameter of a nucleus
3 c P can accommodate 6 electrons
4 a We are using capital letters
5 c A neutron is represented as n0
6 a We are using s, p, d and f
7 c We can using this formula, 2n2 to find out number of electrons
8 c 14 is the maximum number of electrons
1 a 27 protons and neutrons
2 c Maximum 32 electrons
3 b The atoms of different elements with different atomic numbers
4 a Ion or atom or molecule which has the same number of electrons
1 a Any element in group 1 has just one valence electron
2 b Neon lies in 8th column, so it has 8 valence electrons
3 b This is the isotone
4 b Isotope has different number of neutron
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
LEVEL 1 Exercise 1 Single correct objective questions
Class IX C1:What is inside an atom
© Dr. Ravi’s Educational Research and Development Center 2
5 a 1s22s22p63s23p64s23d3
6 a Starting from the right, at group 1A, which is the column that Hydrogen is at the top of, and also includes Sodium. All elements in this group have 1 valence electron
7 b Neutron is neutral in charge
8 b 2 paired and 2 unpaired electrons in p-orbital
9 d Atoms vary in size according to the element, but their diameters are of the order of 1 × 10-8 cm=10-10 m
10 c Another isotope of carbon, which seems to be the one you are referencing, has 6 protons, 8 neutrons, and 6 electrons
11 b The maximum number of electrons which can be accommodated in any energylevel of the atom is given by 2n 2 (where n is the number of that energy level)
12 a Uranium used as nuclear fuel
1 c Atomic theory proposed by John Dalton
2 d Electron was discovered by J. J. Thomson in 1897
3 b Proton discovered byy Goldstein
4 a Paramanu term intrroduced by Maharishi
1 c Hydrogen 1S1
2 d Boron 1S22S22P1
3 b Helium 1S2
4 a Carbon 1S22S22P2
1 c Electron mass is lower than proton mass
2 b Neutron has no charge
3 b Atom is mostly empty
4 Question incorrect
5 d Na has 11 electrons, Na+ has 10 electrons
6 a The more the shell no, more the energy
1 b, c, d Isoelectronic refers to two atoms, ions or molecules that have the same electronic structure and same number of valence electrons
2 a Isotope has similar chemical properties
3 a, d L shell of phosphorus has 8 electrons
Exercise 2 Match the following
Level 2 Exercise 3 Assertion and reason
Exercise 4 One or more than one correct options
Class IX C1:What is inside an atom
© Dr. Ravi’s Educational Research and Development Center 3
4 a, c Electron is in the orbits
5 a,b,c,d all atoms of chlorine contain 17 protons, chlorine-35 and chlorine-37 differ in the number of neutrons each one has.
6 a,b All isotopes of an element have the same number of valence electrons
7 b It has one negative charge
8 a,b, c a distinct kind of atom or nucleus characterized by a specific number of protons and neutrons
9 a, b, c, d All these are shells
10 c 1s^2 2s^2 2p^6 3s^2 3p^6 4s^13d^5
11 d These are called nuceons
12 c It contains 11 protons and 12 neutrons
13 d James Chadwick discovered neutron
14 d The maximum number of electrons that can be filled in a valence shell is eight
Exercise 5: Linked Data Questions
1 b 1:4 is the correct option
2 d Energies are in the ratio 4:1
1 d Valence shell has 10 electrons
2 c Valence shell no is 4 for atomic number 38
LEVEL 3 Exercise 6 Questions from/for Olympiads, NTSE
1 a There are 24 electrons
2 a The diameter of the nucleus is in the range of 1.75 fm (1.75×10−15m)
3 c 11 protons and 11 electrons
4 a The question is Fe2+ has how many unpaired electrons. Fe2+ =[Ar]4s03d6
5 c Nucleus has 25 protons and 30 neutrons
6 d One molecule of oxygen has 16 electrons
7 a Isotopes
8 b ii and iii postulates are true
9 c Dalton’s atomic theory
10 b,c Positively charged nucleus at the centre of atom
11 b Given elements are isobars
12 d Atomic number 9 and mass number 19
13 c Atomic number of the element is 13
14 a K, L has least energy difference
15 c mvr=nh/2
16 d Mass number = 23
Propel Academy
CHAPTER 2 PERIODIC TABLE
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 b According to increasing atomic masses
2 a Ge found place later
3 c Modern periodic table has 18 vertical columns known as groups
4 c Metalloids
5 c E2O3 is oxide of Eka Aluminium
6 a Boron atomic weight is corrected
7 d Noble gases are in VIII A
8 d General electron configuration of d block elements is (n-1)d1-10ns1-2
Serial No.
Answers Explanations
1 a It complete outer shell
2 b The p-block comprises of elements of group 13 to 18
3 b Each period ends with a noble gas having ns2np6
configuration
4 c IV A contain lead
5 b The non metallic nature of boron is due to its smallsize and high ionisation energy
6 a the atomic radius increases as the group and energy levels increase
7 c All these are rare
8 b K easily lose electrons
1 b C,Si, Pb, Sn comprises IVA
2 c These group contain semi metals
3 d It is more reactive element
4 a Bi is the last element in group 15 so it is the most metallic
5 a Electronegativity decreases
6 a Most of the time elements in the same group have the same number of valence electrons.
7 c Valence is constant in groups
8 b Group 14
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
Class IX C2: Periodic Table
© Dr. Ravi’s Educational Research and Development Center 2
9 b Period 2 has k and l shells. Outermost shell is L
10 b F< O < C < Be < Li
1 a Mendeleev’s periodic table is based on Atomic mass.
2 a The law of octave was proposed by Newlands
3 b Al, Si, P, S are belongs to same period
4 b Mendeleev’s arranged 63 elements
5 c Limitation: Electronic configuration resembles of hydrogen and alkali metals .No fixed position for Hydrogen
6 a Newland octaves rule applicable only up to Calcium
7 b Horizontal rows is known as Periods while Vertical columns are known as Groups
8 c Triads are known as a set of three elements having same chemical property
9 a Modern periodic table stated by Mosley
10 c No. of groups 18 & No. of periods 7
11 a Na(11) and K(19) are belongs to same group
12 d Atomic number is 35
13 c I A group element is K
1 a Noble gases have stable electron configuration
2 d Alkali metals can form OH- ions
3 b Modern periodic table is based on atomic numbers
4 b Largest division of periodic chart would be the metals
5 c Boron has less size than Beryllium
6 c Atomic numbers of isotopes are same
7 b Largest atomic size has least ionization potential
8 b First period is the shortest and sixth period is the largest
1 d Highly reactive metals
2 c Heavy metals
3 b Lanthanides
4 a Zero group elements
1 d Highest electron affinity
2 c Oxidation state -1
3 a Highest first IP
4 b Radio active metal
LEVEL 1 Exercise 1 Single correct objective questions
LEVEL 2 Exercise 2 Assertion and reason
Exercise 3 Match the following
Class IX C2: Periodic Table
© Dr. Ravi’s Educational Research and Development Center 3
1 d Metallic character decreases as we move from left to right
2 c Non metallic character increases from left to right across a period
3 b Oxidizing character of elements down a group
1 c N, O, F, Na, mg and Al
2 d
3 a
1 a, b, c Ratio is not a periodic property
2 a, b, c This all will show diaginal relation
3 a, b, c The factors that affect ionisation energy are size of the atom, charge of nucleus and screening effect of inner electrons.
4 a, d (IP1) of N > (IP1) of O
Configuration of N (7) = 1s22s2 2p3
Configuration of O (8) = 1s22s22p4 N is half filled that’s why it requires comparative high
energy to remove electron from it orbit than O. (IP)2 Li > (IP)2 of Ne
(IP)2 means second ionisation potential, Configuration of
Li+ = 1s2
Configuration of Ne+ = 1s22s22p5, Li+ is fully filled
5 a, b, c, d All forms amphoteric oxide
6 c Periods indicates principle quantum no
7 b Refractive index is not a periodic property
8 a,b,d These are the anomalous pairs
9 d Na acts as best reducing agent
10 d 7th period is the incomplete period
11 a,b,c
1 b It Recur after certain regular interval
2 a Diagonal relationship seen between 2nd and 3rd period
3 a Elements of d block are Transition elements & f block elements are known as inner transition element
4 a Elements of 1st group is known as Alkali metal Elements of 2nd group is known as Alkaline earth metal
5 a In all the 3 case an s– electron in the unpaired state is to be removed. In the case of Cu a 4s electron is to be removed which is closer to the nucleus than the 5s electron of Ag
Exercise 4 Linked Comprehension type
Exercise 5 One or more than one correct options
LEVEL 3 Exercise 6 Questions from/for Olympiads & NTSE
Class IX C2: Periodic Table
© Dr. Ravi’s Educational Research and Development Center 4
6 d As the polarising power is increasing so is the order M+1< M+2< M+3< M+4
7 d Both are amphoteric
8 b Both have nearly the same size
9 d K+ has 18 e-, Ca2+ has 18 e- and Ne has 10 e-
10 c d5<P3<d10<p6
11 a Li<Be<Mg
12 c Phosphorous has half filled electronic configuration
13 c Electron addition is easier in O2-
14 a Barium in presence of oxygen gives BaO and BaO2
15 b 6th period has 32 elements
16 a D block has only metals
17 A,c Given options don’t follow Dobereiner’s law
18 b Second element has 2 valence electrons
19 c (n-1)d shell and ns sub shell has less energy difference
20 a I1 has least value
Propel Academy
CHAPTER 3 CHEMICAL BONDING
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 a Attain 8 electrons in outer shell
2 b Valence electrons
3 c Only dots
4 b Electron deficient compounds don’t have 8 electrons
5 a Ionic compounds are solid
6 b Covalent bond
7 b Bad conductors of electricity
8 c Coordinate bond
9 d Covalent compounds not soluble in polar solvents like water
10 a Good conductor of electricity
Introductory exercise 1
Introductory exercise 2
1 b Overlapping of orbitals
2 a Larger atomic size
3 b Covalent bond
4 a Energy is decreasing
5 a Ionization enthalpy
6 b NaCl>CaCl2> MgO
7 b Electron affinity
8 a Strongest bond is ionic
Introductory exercise 3
1 a Sigma bond
2 c Axial overlap of orbitals gives p-p
3 b s-s < s-p<p-p
4 a s-s> s-p> p-p
5 b Pie bond
6 a Sigma bond
7 a 8 sigma and 1 pie bond
8 a Covalent bond
Class IX C3:Chemical Bonding
© Dr. Ravi’s Educational Research and Development Center 2
1 d ClO2 is an exception to octet rule
2 b Negative ion
3 c
4 b
5 d BF3 doesnt follow octet rule
6 a A2B3
7 Question has no correct options
8 b Electrovalent and covalent compounds
9 c MgO has the highest melting point
10 d Fused LiCl would be less conducting than fused NaCl
11 b Electrovalent
12 d C6H12O6 will not conduct electricity
13 d Covalency is equal sharing of electrons takes place between 2 atoms
14 d Atoms of the same size
15 c Dative bond is present in BaCl2
16 c Covalent bond
17 b SiCl4 is non polar
18 c F is most electronegative
19 b V shape is seen in water molecule
20 c Nitrogen covalency is 3
1 c 3 bond pairs and 1 lone pair
2 b 2 bond pairs and 2 lone pairs
3 d 2 bond pairs and 4 lone pairs
4 a 4 bond pairs and no lone pairs
1 d Triple bond
2 a Covalent bond
3 b Ionic bond
4 c Octet configuration
1 a Number of valency electrons in nitrogen atom is 5
2 b Electronic theory of valency is known as chemical bond theory
3 c Iron is less metallic than potassium
4 d Atoms are most stable than molecules
5 d Metallic bond is non directional
6 b
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Match the following
LEVEL 2 Exercise 3 Assertion and reason
Class IX C3:Chemical Bonding
© Dr. Ravi’s Educational Research and Development Center 3
1 a Nitrogen has triple bond
2 a Bond strength is very high
1 a Hydrogen bonding in water
2 a Higher electro negativity of oxygen than sulphur
1 b Lithium
2 a, b, d Lewis symbol of sodium is not Na
3 a,b,c
4 a They are hard solids
5 a,b,c
6 c Acceptor has zero valence electrons
7 a,b,c,d
8 a,b,d Pie bond is not formed by hybrid orbitals
9 a,b,d Ionic compound is electrostatic forces
10 a,c,d Ethyl Alcohol has not hydrogen bond
11 a Covalence of nitrogen is 3
12 b Potassium has the strongest metallic bond
13 b,c,d In polar compounds separation of charges takes place is true
14 a,b,c NH3 has no partial charge separation
15 b,c,d
16 c Ionic bond
1 a Chemical bond
2 a Valence electrons in an atom
3 d
4 a,b,d
5 d CaI2 is least ionic
6 b Ammonium nitrate contains all the three bonds
7 d KCl boils at high temperature
8 c CaO
9 c Soluble in polar solvents like water
10 b Chlorine is more covalent
11 Question has no correct options
12 c Aluminium looses 3 electrons
Exercise 4 Linked Data
Exercise 5 One or more than one correct options
Level 3 Exercise 6 Questions from/for Olympiads
Propel Academy
CHAPTER 4 ACIDS, BASES
AND SALTS Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No
Answers Explanations
1 b Slaked lime is an alkali
2 a organic acids are weak acids
3 b Substances with sour taste called acids
4 a Grape contains tartaric acid
5 b It is soluble in water
6 b Hydrogen gas is liberated
7 a,b Salt and water
1 a pH=-[log4.5 – 3log10]= 3-0.653= 2.347
2 b Replaceable hydrogen atoms
3 a M(1.75)=0.25 x 6 ; m=0.0857, pH=-log0.0857 = 1.07
4 a Mono acids
5 a pH<1 has strong acids
1 b Salts are mostly solids
2 b They have high melting points and boiling points
3 a It is an acidic salt
4 b It is a basic salt
5 b Acid change the colour blue to red
6 b Just like acids and bases, solutions of salts in water conduct electricity
7 b Tooth pastes are basic in nature
8 c Salts
9 c NaCl is salt
10 b Antacids are Mg(OH)2
1 a CO2 is released
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
Introductory Exercise 4
Class IX C4:Acids, Bases & salts
© Dr. Ravi’s Educational Research and Development Center 2
2 b Bleaching powder is CaOCl2
3 c Efflorescence
4 c Gypsum is CaSO4. 2H2O
5 c Bleaching powder on exposure to air liberates chlorine gas
Serial No
Answers Explanations
1 b Carbonic acid H2CO3 is weak acid and H2SO4, HCl, HNO3 are strong acids
2 b This one only react with acid
3 b Neutralisation reaction are always exothermic
Acid + Base salt + water
4 b F>Cl> Br> I (basic strength in decreasing order)
5 c for weak acid
HA (aq) ˆ ˆ †‡ ˆ ˆ H+(aq) + A(aq)
here [H+] = [A]
6 a H3PO4> H3PO3> H3PO2 (Acid strength in decreasing order) H2SO4> H2SO3 (Acid strength in decreasing order)
7 c Down the group acidic strength decrease HNO3> H3PO4> H3AsO4> H3SbO4 (acid strength in decreasing order)
8 c Acidic strength order ClOH>BrOH> IOH (electronegativity decreases)
9 c Bases are bitter in taste
10 b All alkalies are bases but all bases are not alkali. Water soluble bases are called alkalies.
11 B Methyl orange gives red colour with acid
12 a Its molarity is 4
1 b NaOH have one hydroxyl group hence monoacidic
2 c Al(OH)3 is diacidic.
3 a, d Al (OH)3 is amphoteric, act both as acid and base
4 c Ca(OH)2is triacidic
1 b Zn(OH)2 and Al(OH)3 are amphoteric
2 a, d NaOH, KOH, Ca(OH)2 are strong alkalies
3 b, d Zn(OH)2 and Al(OH)3 are amphoteric
4 a, d NaOH, KOH, Ca(OH)2 are strong alkalies
LEVEL 1 Exercise 1 Single correct objective questions
Exercise 2 Match the following
Class IX C4:Acids, Bases & salts
© Dr. Ravi’s Educational Research and Development Center 3
1 a NaOH is a strong alkali
2 a Cold milk has basic properties
3 c Non metallic oxides are only acidic in nature
4 d Plaster of paris is used as plaster by dentists
5 b Acids and bases react to give salt and water
6 a
1 a, c All sulphides are not soluble in water
2 a, b, c, d kw = [H+] [OH] = 10–12
pkw= log kw = log 10–12 = 12
At 250C for H2O
[H+] = [OH] so [H+] = 10–6
pH = log [H+]
= log 10–6 = 6
H2O is neutral here because [H+]
= [OH]
pH = 6.5 means basic solution
3 b, c Water soluble base is alkali
4 a, b, c, d All these react with HCl in one step
5 c, d This base does not turn blue litmus to red
6 d pH = –log[H+] 3 = –log[H+] so, [H+] = 10–3 M Again pH = 6 so, Similarly [H+] = 10–6 M if 10–3 M solution is diluted 1000 times it conc. becomes 10–6 M.
7 c Methyl orange change to yellow colour
8 c Acid soil curved by spraying slaked lime
9 c Alkaline soil curved by gypsum powder
10 a Mg(OH)2 and KOH can be used as antacid to neutralize HCl produced in stomach
1 b HCl H+ + Cl
LEVEL 2 Exercise 3 Assertion and reason
Exercise 4 One or more than one correct options
Exercise 5 Linked Comprehension type
Class IX C4:Acids, Bases & salts
© Dr. Ravi’s Educational Research and Development Center 4
0.01 0.01 M [H+] = 0.01 M = 10–2M
pH = log[H+] = log (10–2) = 2
2 a pH = log[H+]
5 = log [H+] [H+] = 10–5 M So [HCl] = 10–5 M
3 a Given [HCl] = 0.01 M [H+] = 10–2 M
After dilution [H+] = 2
41010
100
pH = log [H+]
= log (10–4) = 4
1 a pOH =9.56
2 b pH = 14 – pOH = 4.435
3 c pH and pOH is 14
1 a Test tube A is acidic
2 b Test tube B is basic
3 b pH > 7
1 a Methyl orange gives red color in acidic medium and yellow in basic medium
2 c Organic acid are weak acids and generally mineral acids are strong acids
3 a Ca(OH)2 + Cl2 CaOCl2 + H2O
4 a It is called dead burnt plaster
5 a CaCl2 is hygroscopic as it absorbs moisture from the air
6 b Efflorescence substance are hydrated crystalline salt which loss their crystalline water at ordinary temperature
7 c Acidity of NaOH, Cu(OH)2 and Fe(OH)3 are 1, 2, and 3 respectively
8 d all these are epsom salt
9 c Two or more crystalline forms are called polymorphs
10 a It is a neutral oxide
11 a Bleaching powder has oxidising properties
12 d It is a double salt
13 b Pb(OH)NO3 is a basic salt. It has one OH ion which can be replaceable
14 c It is used as fire extinguisher
15 c pH range is 7 to 7.8
16 d pH = 10
17 c Epsom salt is magnesium sulphate
LEVEL 3 Exercise 7 Questions from/for Olympiads & NTSE
Class IX C4:Acids, Bases & salts
© Dr. Ravi’s Educational Research and Development Center 5
18 a Formic acid and ammonium hydroxide
19 a pH=-log4.3x10-4=4 – log 4.3 = 4 – 0.633 = 3.367
20 a Orange
21 c Nature of salt is neutral
Propel Academy
CHAPTER 5 CARBON AND ITS
COMPOUNDS
Chemistry
© Dr. Ravi’s Educational Research and Development Center 1
Serial No.
Answers Explanations
1 d CO2 is not an allotrope
2 d Fullerenes were discovered by H.W. Kroto, R.F. Curl and R.E. Smalley in 1985
3 c Diamond naturally occurring allotrope
4 d Graphite is soft material
5 a Methane contains C and H
6 a It has different forms
7 b C arranged as hexagonal rings
8 c It has tetra valency
1 d There are four single bonds, and no lone electron pairs in the methane molecule
2 d Double bonds in saturated hydrocarbons is zero
3 a The difference in the molecular masses of any two adjacent homologous is 14u
4 a Vinegar contains acetic acid
5 b They are fatty acids
6 d Alkynes is CnH2n-2
7 b Propane is C3H8
1 b Soaps are sodium salts of carboxylic acids
2 a Photochemical
3 c Nickel is catalyst
4 b Oxidation method
5 d Isomerism
6 a Single bonds
1 d Liquid petroleum gas (LPG), kerosene, petrol, plastics are carbon compounds
2 a Allotropes existence of the same element in various physical forms
e.g. diamond and graphite
Introductory Exercise 1
Introductory Exercise 2
Introductory Exercise 3
LEVEL 1 Exercise 1 Single correct objective questions
Class IX C5: Carbon & its compounds
© Dr. Ravi’s Educational Research and Development Center 2
3 a Diamond and graphite and fullerene are allotropes of carbon
4 d Because of diff properties
5 d Diamond has tetrahedral crystal arrangement
6 a Diamond is an allotrope of carbon
7 d Diamond, graphite and fullerene are crystalline form of carbon. While coke is amorphous
8 d Diamond is bad conductor because it not have free electrons. Graphite is good conductor of electricity
9 b Ethanoic acid
10 b Methane, carbon monoxide and water
11 C,d
12 a Urea is first organic substance made in laboratory
1 a Graphite is a non metal
2 b Carbon has alot of properties
3 d Pentane is C5H12
4 b Pentane has three chain isomers
5 b All saturated hydrocarbons are aliphatic hydrocarbons
6 d Alkene is c4H8
7 b
8 b Aromatic hydrocarbon is benzene C6H6
1 d Esterification reaction
2 a Addition reaction
3 b Substitution reaction
4 c Neutralisation reaction
1 c Alcohol
2 d Carboxylic acid
3 a Ketone
4 b Alkene
1 a Since B is an acidic which on heating with A in presence of a few drops of conc. H2SO4 gives a sweet smelling compound C, therefore C must be an ester and A must be an alcohol. Since A is an alcohol with MF C2H6O, it must be ethanol (CH3CH2OH)
2 d Since ethanol (A) on oxidation with K2Cr2O7/H2SO4 gives an acid (B), therefore, acid (B) must be ethanoic acid.
3 d If A is ethanol and B is ethanoic acid then C must be ethyl ethanoate.
4 d Esterification reaction
Exercise 2 Assersion and Reason
Exercise 3 Match the following
Exercise 4 Linked Comprehension type
Class IX C5: Carbon & its compounds
© Dr. Ravi’s Educational Research and Development Center 3
5 a Oxidation reaction
1 a, c Carbon structural with these two
2 a, b, c These three have sigma and pi bond
3 a, b, c Hese have double bond
4 b, c Benzene and naphthalene are aromatic
5 a, b, c, d All these contain bond
6 a CNG and LPG are hydrocarbon
7 c alkaneCnH2n + 2 ,alkene CnH2n, Alkyne CnH2n- 2
8 b Cyclohexane, Butane and Isobutane are saturated hydrocarbon. Benzene are unsaturated hydrocarbon
9 a Ethene, Benzene and ethyne contain multiple bond
10 c Homologue have – CH2 difference
ethane (C2H6) + CH2 C3H8 (propane)
11 c Ethyl Ethanoate is Ester
12 a,c,d 1 mole of ethyne on complete combustion gives 4 moles of CO2 and 2 moles of H2O
13 b,c,d Option A is homologous series
1 d Ionic bond formed by complete transfer of electron while covalent bond Formed by mutual sharing of electron. It is due to 4 valence electrons
2 a Alkynes have the shortest bond length
3 b Ethanol is basic in nature
4 a
5 c Ethene produced when ethanol is heated with excess of con H2SO4 at 443 k
6 a Vinegar has acetic acid
7 b Propyl Ethanoate
8 b
9 b Alkyne has triple bond i.e C3H4
10 b General formula of alcohols is CnH2n+1OH
11 d Propane has 8 C-H bonds
12 a Urea is first lab made organic substance
13 c Napthalene is not hydrocarbon
14 a Butane and Iso butane have the same molecular formula
15 b Saponification means alkaline hydrolysis of ester
16 a Soap is C18H37COONa
17 b Detergents do not precipitate in hard water
18 b Degradation of organic wastes in absence of air gives methane, hydrogen, nitrogen and carbon dioxides
19 d Magnesium oxide
20 c Benzene
Exercise 5 One or more than one correct options
LEVEL 3 Exercise 5 Questions from/for Olympiads & NTSE
Top Related