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Chemistry Paper 12 Section I (40 Marks) (Answer all the Questions)

Question 1

a) Select the correct answer: [5]

1. Identify the halogen : Iodine, Radium, Argon.

2. Bleaching action of chlorine is permanent because it takes place by ____ [oxidation /Reduction/Redox reactions].

3. ____burns in oxygen to give a basic oxide [Mg/Zn/Al].

4.Concentrated nitric acid is converted to sulphuric acid by reaction with

____[so2/s/concH2SO4].

5.Carbon monoxide reacts with chlorine in the presence of ____[heat/sunlight/cao] to give phosgene.

b) Name or State the following: [5]

1. The lightest element.

2. The group from the groups IA, IIA, VIA and VIIA whose elements are most electronegative. 3. Two metals which are both malleable and ductile.

4. An element A has electronic configuration of 2,8,1 whereas another element B has electronic configuration 2,8,3 which of the elements is more reactive. 5. Name one metal more reactive and another less reactive than hydrogen.

c) Write a balanced Chemical equation by combining the given substances :- [5]

1. Coke + Steam. 2. Potassium + Nitrogen. 3. Calcium + Nitrogen.

4.Sulphur + Carbon. 5. Sodium + Chlorine.

d) Change the following statements by replacing the underlined words : - [5]

1. Oxidation reaction is the gain of hydrogen.

2. Substances which influence the rate of reaction by improving the efficiency of a catalyst is called a inhibitors.

3. Electrons carry no electric charge and are neutral.

4. Dobereiner introduced the law that every eighth element was a repetition of the first.

5. When sulphur di oxide gas dissolves in water it forms sulphuric acid.

e) Mention the TERMS used for each of the following :- [5]

1. Temperature at which liquid changes rapidly into the gaseous state without any further change in temperature.

2. Temperature remaining constant, volume of a given mass of a dry gas is inversely

proportional to its pressure. 3. A group of atoms of elements that behaves like a single unit and shows a valency. 4. The physical and chemical properties of elements are periodic functions of their atomic numbers. 5. Elements of both Lanthanide and Actinide series.

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f) Pick the ODD one out : - [4] 1. An element copper shows variable valency _____ [Cu1+, Cu2+, Cu3+]. 2. Periodic properties include _____ [ Valency, Ionisation, Metallic & Non Metallic

properties]. 3. Sub-atomic particles are found in the centre of _____ [protons, electrons, neutrons]

nucleus of an atom. 4. Physical properties of CO2 ___ [colourless, combustible odourless]. g) 1. What do you observe when : - [2] a) Heated iron is introduced in a jar of Cl2 .

b) Water is added slowly to quick lime. 2. Give reasons for the following :- [2] a)It is dangerous to sleep in a closed room with a coal fire burning. b)Animals die in an atmosphere of Nitrogen. 3.Complete and balance the following equations: [1] a) PbO2 + 4HCl b) 3CuO + NH→ 3 → h) 1.Write chemical formula of the following: [1] a). Nitrolim. b) Gypsum. 2. Write chemical name of the following compounds: [2] a) KClO.b) KClO4

3. Calculate the molecular weight of calcium hydroxide. [2] [At weight Ca = 40, O = 16, H = 1] i ) A colourless, odourless gas which is neutral to litmus. which burns with a pale blue flame

producing a pop sound. 1. Identify the gas. 2. Give the equation. [1]

Section B (40 Marks) (Answer Any Four Questions)

Question 2. a) Fill in the blanks : [6] The period -1 contains ____elements, and periods - 2 and 3 ____elements each. There are

___ horizontal rows called periods, and ___ vertical columns called groups. An element in period -3 will have __electronic shells or orbits and in group VA will ___ valence electrons in its outermost shell. [2/3/5/7/8/10/18].

b) Copy and complete the following table : - [4]

Property Rhombic Sulphur Plastic Sulphur

Colour

Nature

Crystal Shape

Solubility

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Question 3 a) Justify the use of :- [4] 1. CO2 - manufacture of aerated drinks. 2. Cl2 - sterlization of water. 3. CO - as a fuel. 4. N2 - tinned food products. b) The diagram represents the preparation of oxygen from KClO3 & MnO2 [4]

1. State why the test tube is kept in the inclined position. 2. Name the residue left behind in the test tube after the completion of the reaction. 3. State why the delivery tube is removed from the trough before the heating is stopped. 4. Give the chemical equation for the above reaction. c) Classify the following as Oxidation or Reduction with respect to the underlined substance [2] 1. CuO + H2 Cu → + H2O. 2. 2FeCl2 + Cl2 2 FeCl→ 3.

3. Br2 + H2S 2HBr→ + S. 4. 2 KI + H2O2 I→ 2 + 2KOH. Question 4.

a) Match the form of sulphur or its compound from list I with its correct application from

List II. [5]

List – I 1. Powdered Sulphur 2. Colloidal Sulphur 3. Metallic thiosulphates 4. Calcium bisulphite 5. Sulphur trioxide

List - II A) Sulphuric acid manufacture B) Gun Powder C) Paper industry D) Photography E) Medications.

b) A gas occupies 700ml at S.T.P. Find the volume occupied by the gas when its pressure is

400mm of Hg and its temperature 15oC. [5] Question 5.

a) Define the following : - [3] 1. Boyle’s law. 2. Mendeleev’s periodic Law. b) Draw electron dot diagram to depict the formation of NaCl from 11Na23 & 17Cl35 [2] c) Reactions can be classified as : [5] A) Direct combination B) Decomposition C) Simple displacement D) Double

decomposition E) Redox reaction. State which of the following types takes place in the reactions given below : i) Cl2 + 2KI→ 2KCl + I2 ii) 2Mg +O2 → 2MgO. iii) SO2 + 2H2O + Cl2 2HCl +

H2SO4. →

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iv) AgNO3 + HCl→ AgCl + HNO3. v) 4HNO3 4NO2 + 2H2O +O2. → Question 6.

a) The diagram represents an apparatus used for water of crystallisation of hydrous copper [II]

sulphate crystals [5]

1. Name the substance ‘A’ found in the test tube with its Molecular formula. 2. What was the color of ‘A’ before heating? 3. Define the term crystallisation? 4. Give a chemical equation for the above reaction. 5. What is the nature of substance ‘B’ after heating? b) Fill in the blanks : [5] 1. In the formation of an ionic bond ___ of electrons takes place, while in the formation of a

____ bond, sharing of electrons takes place. 2. The ionic character of a covalent bond is due to the differences in the ___of bond forming

elements. 3. Ionic bond is favoured by a ___ value of ionisation potential and ____value of electron

affinity. Question 7. a) Give the atomic numbers of the following [6] 1. Second alkali metal. 2. Second halogen.3. The element with three unpaired electron. 4. The element with the largest electroneagtivity. 5. The element with the smallest

ionisation energy in the 4th period. 6. The first transition element. b) Mention the raw materials used in the manufature of i) Urea ii) C.A.N. [4]

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Chemistry Paper 13 Section I (40 Marks) (Answer all the Questions)

Question 1. a) Select the correct answer : [5] 1. ___ burns in oxygen to give a amphoteric oxides. [Ca/Al/N2]. 2. A colourless sulphide is ___[CuS/P4S3/CS2]. 3. Bleaching action of sulphur is temporary because it takes place by

___[Oxidation/Reduction/Redox reactions] 4. ____ burns in oxygen to give a acidic oxide [K/Pb/c]. 5. The dilute acid which reacts with marble chips to give a soluble salt is ____[ dil. H2SO4 /

dil. HNO3/dil.HCl]. b) Name or state the following: [5] 1. The most electronegative Halogen: 2. The group containing the element ‘X’ having eletronic configuration 2,8,3. 3. One metal which has a low melting point. 4. In nature, metal A is found in a free state while metal B is found in the form of its

compounds. Which of these two will be nearer to the top of the activity series of metals? 5. Name the metal which has been placed at the top of the reactivity series. c) Write a balanced chemical equations by combining the given substances: [5] 1. Water gas + excess steam. 2. Sodium + Hydrogen. 3. Magnesium + Nitrogen. 4. Hydrogen + Sulphur. 5. Iron + Chlorine.

d) Change the following statements by replacing the underlined words:- [5] 1. Oxidation reaction is removal of electronegative element. 2. Substances which act as catalytic poisons and retard the efficiency of a catalyst are called

promotors. 3. Electrons have a neutral charge. 4. Newland introduced the law of triads. 5. When sulphur trioxide gas dissolves in water it forms sulphurous acid. e) Mention the TERMS used for each of the following:- [5] 1. The process of change from liquid state to a gaseous state. 2. Temperature remaining constant the product of the volume and pressure of a given mass

of a dry gas is constant. 3. A molecule of a substance i.e elements or compound could be represented by symbols. 4. The physical and chemical properties of elements are periodic functions of their atomic

weights. 5. Series if elements from Thorium 90Th to Lawrencium 103Lr in [period - 7]. f) Pick the odd one out:- [4] 1. An element Iron shows variable valency ____[ Fe3+, Fe2+, Fe1+]. 2. Attempted to classify elements in increasing order ___[Newland, Doberriner, Moseley] of

their atomic weight. 3. Atom as a whole, is electrically neutral because it contains equal number of ___[protons,

neutrons, electrons]. 4. Physical properties of Cl2 ___ [greenish yellow, choking combustible]. g) 1. What do you observe when :- [2]

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a) A piece of white phosphorus is placed in a jar of Cl2.

b) Quick lime is heated with oxyhydrogen flame. 2. Give reasons for the following :- [2] a) It is dangerous to stand in a garage with the engine of an automobile running. b) N2 gas not collected over air. 3. Complete and balance the following equations :- [1] a) NaOH + CO2 b) H2O + Cl2 → → h) 1. Write chemical formula of the following :- [1] a) Bleaching Powder. b) Marble chips. 2. Write chemical names of the following compounds. [1] a) (NH2)2 CO. b) C6H12O6 . 3. Calculate the molecular weight of sodium chloride. [At weight Na = 23; Cl = 35.5]. [2] i)A colourless odourless gas which is neutral to litmus which turns white anhydrous copper

sulphate blue 1. Identify the gas. 2. Give the equation. [2]

Section B (40 Marks) (Answer Any Four Questions)

Question 2 a) Study the extract of the periodic table and answer the following:- [6]

11 Na 23

12 Mg 2413 Al 27

14 Si 2815 P 31

16 S 3217 Cl 35.5

18 Ar 40

1. What is the name given to the elements that belong to the same group as Magnesium? 2. Identify the metalloid. 3. Which element forms an amphoteric oxide. 4. Which element has stable electronic configuration? 5. Which element exists in isotopic forms. 6. Which element has valency 3? b) Copy and complete the following table:- [4]

Property Co Co2

Litmus Test

Solubility

Combustibility

Lime water

Question 3. a) Justify the use of :- [4] 1)CO2 - manufacture of Urea. 2) CO - in the extraction of metals from their ores. 3) Cl2- bleaching. 4) S- used in match industry. b) The following diagram shows the preparation of Co from formic acid and a substance X. [4]

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1. Identify the substance ‘X’. What is its purpose in the preparation? 2. How is the gas collected and why? 3. Write one chemical test to identify the gas? 4. Give a balanced chemical equation for the above preparation? c) Classify the following as Oxidation or Reduction with respect to the underlined substances. [2] 1. 2FeCl2 + Cl2 2FeCl→ 3 2. CuO + H2 Cu → + H2O. 3. Zn + H2SO4 ZnSo→ 4 + H2. 4. Br2 + H2s → 2HBr + S. Question 4. a) Hydrogen gas is a strong reducing agent, when metallic oxides is reduced to metals it

changes its colour. Identify the colour change in each case. [4] 1. ZnO + H2 Zn + H2O. 2. Fe2O3+3H2 2Fe + 3H2O. → → 3. PbO + H2 Pb + H2O. 4. CuO + H2 Cu + H2O. → → b) Define the term Hydrogenation of oils. [2] c) Name the following : [4] 1. An efflorescent deca hydrate salt. 2. An deliquescent salt of a trivalent metal. 3. A liquid hygroscopic substance. 4. An acidic gas which reacts with water to give two

acids. Question 5. a) A gas ‘X’ at 15oC is heated until its pressure doubles and volume triples from the original

pressure and volume. If the original volume is 1000CC. Calculate the temperature to which it should be heated. [5]

b) Fill in the blanks from the words given below: [Mixing, Identification, absorption, adsorption, adsorbent cotton, cellulose, sand,

separation]. Chromatography is a technique for ___ and ___of substances present in complex mixtures. Separation of constituents of a mixture is based on the difference in ___ of different constituents on the surface of the ____ medium, preferably made of ___. [5]

Question 6 a) Give a balanced chemical equations:- [5] 1. Acetylene + oxygen→ carbon di oxide + water. 2. Slaked lime + dilute Hydrochloric acid calcium chloride + water. → 3. Bleaching powder + ammonia calcium chloride + water +Nitrogen. → 4. Ammonium di chromate chromium oxide + water + oxygen. → 5. Lead oxide + ammonia→ lead + water + Nitrogen. b) With reference to the long form of periodic Table. Fill in the blanks with appropriate words. [5] 1. If an element ‘X’ has atomic number 18, then its valency is ___ [ +1, +1, 0].

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2. An element ‘Y’ has atomic number 20. It finds position in period ___[2,3,4] and group _____[I, II, III].

c) Copy and complete the following :-

Element Electronic configuration

Valency Metal/Noble gas/Non-Metal.

15P31 _____ _____ Non-Metal.

18Ar40 _____ 0 _____

13Al27 2,8,3 _____ _____

6C12 _____ 4 _____

Question No. 7

1) Write chemical formulae for the following compounds. a) Potassium chloride. b) Potassium hypochlorite. c) Potassium chlorite. d) Potassium chlorate. e) Potassium per chlorate.

[5] 2) Distinguish between : - a) Oxidation & Reduction reactions. b) Cations & Anions. 3) Write word equation for the following:- [5] a) 3Mg + N2 →Mg3N2. b) 2Zns + 3O2 2Zno + 2SO2 → c) Na2CO3 + 2HCl 2NaCl + H2O + CO2. →

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Chemistry Paper 14 Section A (40 Marks) (Answer all the questions)

Question 1. a) Select the correct answer :- [5] 1. Calcium oxide dissolves in water to give ____[lime stone, slaked lime, milk of lime]. 2. Identify the alkali metal : Copper, Sodium, Lead. 3. The reaction of nitrogen with ____. [O2/H2/Cl2] under specific conditions is called Haber’s

process. 4. Sulphur burns in air or oxygen to give ___ which dissolves in water to give ___[ SO2,

SO3, H2SO3, H2SO4]. 5. Chlorine reacts with H2S to give __as the oxidized product [S,SO2,SO3] b) Name or state the following: [5] 1. The most reactive alkali metal. 2. The group which contains the elements having electronic configuration 2,7 and 2,8,7. 3. A metal which is so soft that it can be cut with a knife. 4. If A, B, C, D, E, F, G, H, I, J and K represent metals in the decreasing order of their

reactivity, which one of them is most likely to occur in a free state in nature? 5. The metal which has been placed at the bottom of the reactivity series. c) Write a balanced chemical equations by combining the given substances:- [5] 1. Methane + steam. 2. Calcium + hydrogen. 3. Aluminium + hydrogen. 4. Sulphur +chlorine (gas). 5. Carbon di oxide + coke. d) Change the following statements by replacing the underlined words:- [5] 1. Oxidation reaction is addition of electro positive element. 2. A catalyst which decreases the rate of a chemical reaction is called a positive catalyst. 3. Protons have a negative charges which are emitted from the cathode. 4. Moseley stated that properties of elements are periodic functions of their atomic weights. 5. When carbon di oxide gas dissolves in water it forms carbon mono oxide. e) Mention the TERMS used for each of the following:- [5] 1. The process of change from liquid state to solid state at a particular temperature. 2. Pressure remaining constant the volume of a given mass of dry gas is directly proportional

to its absolute temperature. 3. A short and scientific notation of an element. 4. Atoms of the same elements having same atomic numbers but different atomic weights. 5. Elements from cerium 58Ce to Lutetium 71Lu in period 6. f) Pick the ODD one out :- [4] 1. An element Lead shows variable valency ____ [ Pb2+, Pb3+,Pb4+ ]. 2. Attempted to classify elements in increasing order ____[ Newland, Mendeleev, Moseley]. 3. Nucleous includes ___ [ protons, neutrons, electrons] inside the nucleus. 4. Physical properties of CO ___________ [ colourless, odourless, non-combustible]. g) 1. What do you observe when:- [2] a) A burning candle is introduced in a jar of Cl2 b) Water is added to slaked lime.

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2. Give reasons for the following:- [2] a) It is dangerous to smoke or be in the vicinity of smokers. b) Nitrogen obtained from air is slightly heavier than Nitrogen obtained from chemical

compounds. 3.Complete and balance the following equations. :- a) NH4OH + H2SO4 → b) Na2SO3 + HCl [1] → h) 1. Write chemical formula of the following [1] a) Slaked lime. b) Silica. 2. Write chemical name of the following compounds. [1] a) HNO2 b) NaAlO2. 3. Calculate the molecular weight of calcium sulphate [At weight Ca = 40, S = 32, O =16]. [2] i) A colourless gas which is neutral to litmus rekindles a glowing wooden splinter. What

happens to pyrogallol solution. [2]

Section B (40 Marks) (Answer Any Four Questions)

Question 2. a) Complete the table pertaining to the following elements given in Coloumn I. [5]

Column IElements

AtomicNumber

ElectronicConfiguration Group

Underline theelement present in

that group

1)Hydrogen 1 ___ IA Be/Na/Ca

2)Carbon 6 ___ N/P/Si

3)Nitrogen 7 ___, ___ ___ C/P/S

4)Oxygen 8 ___, ___ ___ N/S/Cl

5)Sulphur 16 ___, ___, ___ ___ O/N/F

6)Chlorine 17 ___, ___, ___ ___ I/O/S

b) Copy and complete the following table. [5]

Property Diamond Graphite

Colour

Nature[rigidity]

Conductionof electricity

Density

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Question 3

a) State the use of the following:- 1) Coal 2) Coke 3)Gas carbon 4)Lamp Black. [4] b)

[4] i) Name the solution ‘A’ added through the thistle funnel. ii)State the function of the substance ‘B’ when placed in the round bottom flask. iii) State the function of the substance ‘B’ when reacted with concentrated HCl in the

laboratory preparation of chlorine. iv) Give a balanced equation for the above method of preparation of oxygen. [2]

c) The oxygen prepared above is collected by the downward displacement of water. i) Give a reason why oxygen is not collected by the upward displacement of air. ii) Name two other gases, collected by the upward displacement of air during their

Laboratory preparation. Question 4

a) Select the correct answers from the answers A, B or C given: [5] 1. An acidic oxide of Nitrogen A) N2O B) NO2 C) NO. 2. A nitrogenous fertilizer A) calcium cyanamide B) Super phosphate of lime C) Potassium nitrate. 3. An inert gas preferred in electric bulbs A) Nitrogen B) Argon C) Helium. 4. A gas other than nitrogen, slightly soluble in water & difficult to liquefy. A) CO2 B) SO2 C) O2 5. An unstable non-sublimate salt A:(NH4)2CO3 B: NH4 NO2 C: NH4NO3 .

b) Define rusting: [1] c) State your (i) observations, (ii) Name the product formed and (iii) Give the action on litmus

solution when the following substances are separately placed in jars of O2 [4]

i) Glowing charcoal ii) Burning Sulphur.

Question 5

a) Name a non metallic oxide which is a reducing agent. [1] b) Name two crystalline allotropes of sulphur for each allotrope give a sketch of the shape of its

crystals which sulphur allotrope is stable at room temperature.Explain the term vulcanization [5] c) Complete the statement given below by filling in the blanks with the correct word from the

bracket. Oxidizing agents are good ____[donors / acceptors] of electrons. Chlorine has ___ [one/seven] electron is short in the outermost shell and hence readily ___ [accepts/donates] electrons from ___[Oxidizing/reducing] agents. [4]

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Question 6

a) Write balanced equation for the following:- Boiling a solution of magnesium bi carbonate. [2]

b) What is the function of [3] i) Concentrated H2SO4 in the preparation of CO from oxalic acid. ii) How would you convert CO to CO2.

iii) Baking soda is sodium hydrogen carbonate. What is baking powder. c) Complete the table given below:

a) Heat on copper nitrate. Colour of acidic gas evolved ____. b) Heat on iodine crystals. Colour of vapours evolved ___. c) Heat on ammonium di chromate . Name a neutral gas evolved ___. d) Heat on Mercury [II] oxide . Test for gas evolved ____. e) Heat on lead [IV] oxide. Colour of residue _____. [5] Question 7. a) At certain temperature, a gas occupies a volume of 45 litres. At 7oC, the volume is changed

to 42 litres, at constant pressure. What is the initial temperature. [5] b) Mention the TERMS for the following statements given below:

1. A short hand form of a chemical change. 2. A chemical which absorbs moisture. 3. A space occupied by a fixed mass of a gas. 4. A distribution of electons in different shells. 5. A reaction involving addition of electronegative element to a substance. [5]

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Chemistry Paper 15 Section A (40 Marks)

(Answer All The Questions)

Question 1.

1. Name the ions present in each of the following compounds. Write its formulae. [5] a) A compound “A” reacts with dilute hydrochloric acid to give brisk effervescence & if

passed through lime water, it turns lime water milky. b) A compound “B” reacts with Barium chloride to form a white precipitate. c) A compound “C” reacts with concentrated sulphuric acid to give reddish brown fumes. d) A compound “D” reacts with silver nitrate to give a curdy white precipitate. e) A compound “E” reacts with concentrated sulphuric acid to give colourless fumes. These

fumes on exposure to Ammonium hydroxide gives copious evolution of white fumes. 2. Copy the sentences followed by the correct answer. Underline the blanks. [5] a) The bond possible between sodium and chlorine is ____ [ionic/covalent/polar covalent]

and the formulae is ____ [NaCl2 / NaCl / NaOCl]. The compound is a ____[conductor/insulator] in solution. It is used as ____[Table salt/Quaternary salt/double salt] and it is ___[acidic/basic] in nature, when dissolves in water.

b)Hydrogen chloride molecule is a ___ [Ionic /covalent/polar covalent]. The bond is so

called if the shared pairs of electrons are ____ [equally/unequally/symmetrically] between the two atoms _____ [Hydrogen/Chlorine/Hydrogen chloride] is more electronegative element. Hence hydrogen develops _____charge and chlorine develops ___charge on it [ ,δ δ+ − ]. [5]

3. The following statements are incorrect. Change a word or two to correct them. Write the

full sentences. [5] a) When concentrated sulphuric acid is heated strongly it decomposes giving sulphur

trioxide oxygen and water. b)When carbon di oxide and ammonia in the ratio 1:3 by volume are passed into reactor

with a pressure of 378 atmospheres and temperature of 473K. Ammonium carbonate is formed.

c) The outer most shell in potassium atom M shell. d) CAN is a phosphorus fertilizers. e) Chlorine gas is a powerful reducing agent. 4. a) Match the atomic numbers. 9,19,4,18 and 24 with each of the following: family of

element - Transition metals, inert gases, Alkaline earth metals, Alkali metals, Halogens. [5] b) Write the electronic configuration for Cl-, Ca2+, S4-, O-1, N-3 [Cl = 17, Ca = 20, S =16, O =8, N = 7] [5] 5. a)What is the difference between the following pairs. [6] 1) An orbit and an orbital. 2) Atomic number and atomic weight.3) Ground state and excited

state. b) Give an equations for the following: [4]

1. Cl2 + H2O 2. N2 + H2 3. S + Cl2 4. K2Cr2O7 + H2SO4+SO2 → → → →

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Section B (40 Marks)

(Answer Any Four Questions)

Question 2 a) Give balanced equations for the conversations. A, B, C, D & E. [6]

Give equations for the flow diagram given above, mentioning clearly the reactants. b) 7cm3 of a gas is heated from 25oC to 125oC at constant pressure. Calculate the final volume. [1] c) What is the reaction at the catalytic tower in the Habers process and the contact tower of the

contact process. [2] d) Calculate the percentage of potassium by mass in potassium chlorate [K = 39.1, Cl = 35.45, O = 16]. [1] Question 3 a) Give reasons why:- [5] 1) Fractional distillation and not a separating funnel is used for separating a mixture of

methyl alcohol and water. 2) Silver salts are generally kept in dark coloured bottles.

3) Frasch process for extraction of sulphur is more advantageous compared to the sicilian process.

4) Allotropes of carbon exhibit a variation in physical properties. 5) Table salt turns into moist lumps especially during the rainy seasons. b) The diagram represents an apparatus used for separating liquid -liquid mixtures. [5]

1. Name the apparatus seen in the diagram for separating liquid - liquid mixtures. 2. State the type of liquids separated by using the apparatus. 3. If petrol and water use to be separated what will be present in B. 4. Can Methyl and ethyl alcohol be separated by this method. Give reasons. 5. Can KNO3 and NaNO3 solutions be separated by this method, give reasons.

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Question 4 a) A compound of carbon, hydrogen and oxygen contains these elements in the ratio by mass

6:1:4. Calculate its empirical formula. [2] b) Select the correct salt from list II which on thermal decomposition exhibits the change in

colour from list I [5]

Sl.No. List I List II

1. Light green to black A. Mercuric oxide.

2. White to yellow B. Copper carbonate

3. Blue to Black C. Red Lead.

4. Orange to green D. Copper nitrate.

5. Dark red to yellow E. Ammonium di chromate

6. F. Zinc nitrate.

c) Give equations for the following:- [3] i) Sulphur reacting with excess of oxygen gas. ii) Chlorine gas is exposed to water. iii) Concentrated sulphuric acid is added to oxidic acid. Question 5 a) Choose the odd one out form the following. Explain your choice. [5] 1. Li, Na, K, Rb, F 2. Sodium carbonate, copper sulphate, Zinc nitrate. 3. L, K, A, M 4. Hydrochloric acid, sulphuric acid ,ntric acid 5. Blue vitriol ,green

vitriol, white vitriol, yellow vitriol. b) Arrange in increasing order the following as per instructed. [5] 1. Cl, I, Br, F (Electronegativity) 2. Ar, Ne, He, Kr (Number of shells) 3. Catalytic, dilution, oxidation, absorption, (order of towers in contact process) 4. L, K, M, N (density of electrons). 5. K2Cr2O7 , KMnO4 , CrO2Cl2 , MnCl2 , ( order of oxidation of Cr & Mn). Question 6 a) Name the type of reactions in the following cases and product formed: [3] 1. When hydrogen sulphide reacts with chlorine gas. 2. Sodium metal reacts with chlorine

gas. 3. Ethyl alcohol reacts with oxygen gas. b) The diagram represents an experimental verification of a physical property

of hydrogen. [5] 1. State why hydrogen initially in jar A, is later found in jar B. 2. How is the presence of hydrogen in jar ‘B’ proved. 3. If a burning candle is later pushed inside jar ‘B’ will it get extinguished or

continues burning. Give reasons. 4. If jar ‘B’ is later placed in a trough of water, state why the water does not

rise up in the jar. 5. Differentiate between the combustibility of pure hydrogen and hydrogen-

air mixture. c) Give the chemical composition of the following salts :- [2]

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i) Washing Soda. ii) Gypsum. Question 7 a) Name the following:- [8] 1. A non-metal in group VII A of periodic table, which is a solid at ordinary temperature. 2. The salt formed when aluminium reacts with concentrated sodium hydroxide solution . 3. An example of a mixed acid anhydride. 4. A basic gas obtained when nitrogen reacts with hydrogen under specific conditions. 5. The gas which combines with oxygen to give Nitrogen di oxide. 6. The process involving hydrogen used in the manufacture of vegetable fat. 7. The type of oxide formed by the element in period 3 and group III A. 8. The most abundant element in the earth’s crust.

b) 450ml of oxygen gas is collected at 270C. If the volume has to be reduced to 13

of its

original volume, Find the temperature to which the gas has to be cooled? [2]

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Chemistry Paper 16 Section A (40 Marks)

(Answer All The Questions)

Question 1 a) Which of the substances given below from A to E are used as reactant for the laboratory

preparations of the gases given below 1 to 5. [5] A: Zinc B: Oxalic acid C: lime stone D: Sodium Peroxide E: Manganese di oxide. Gases prepared - 1: Chlorine 2: Hydrogen 3: Carbon mono oxide 4: Oxygen 5: Carbon di

oxide.

b) Arrange the following in the increasing order of . [5] 1) electron affinity F, I, Br, Cl. 2) atomic radii Na, Be, Mg, F. 3) electronegativityAl, Si, B,

o. 4) Ionisation Potential Ar, k, Na, Cl. 5) Ionic radii , , ,F Br Cl I− − − −

c) State the technical term for the following : [5] 1) It is a group of atoms of elements that behaves like a single unit and shows valency. 2) A chemical reaction which involves oxidation and reduction simultaneously. 3) Substances which can readily absorb or remove moisture from other substances. 4) The process of addition of hydrogen to organic compounds in the presence of a catalyst. 5) The process of heating natural rubber with sulphur to a definite temperature for a known

period of time.

d) Copy and complete the table given below which gives the summary of the fire extinguishers [5]

FireExtinguishers

Solution incylinder

Solution inglass bottle

Solution/Foamejected out fromnozzle

Soda acidtype

Foam type

e) List 1) Formic acid (HCOOH) 2) Sulphuric acid. [5] i) State the meaning of term ‘acid’? ii) Which is an organic acid and which is mineral acid. iii) Which is monobasic acid? iv) Name the weak acid among the following. v) Which is a strong electrolyte and why?

f) Classify the chemical reactions whether they are A: Exothermic reactions B: Endothermic reactions C: Photochemical reactions

D: Electrochemical reactions E: Reversible reactions. [5] Chemical reactions : 1. 2H2O → 2H2 + O2. 2. C + O2 → CO2. 3. N2 + O2 2NO. → 4. H2 + Cl2 2HCl. 5. N2 + 3H2 2NH3. → →

g) State your observations only in the following cases. [5] 1. When a paste of sodium chloride salt is ignited to the flame. 2. When ammonium di chromate crystals are heated strongly in a test tube. 3. When sodium chloride salt is heated with concentrated sulphuric acid solution. 4. The moist starch iodide paper is introduced into jar of chlorine. 5. When metallic carbonate salt reacts with dilute hydrochloric acid.

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h) Balance the following chemical equations. [5] 1. C6H6 + O2 CO2 + H2O + . → 2. Ca(HCO3)2 + HNO3 Ca(NO3)2 + CO2 + H2O. → 3. KMnO4 + HCl KCl +MnCl2 + H2O + Cl2. → 4. MnO2 + NaCl + H2SO4 NaHSO4 + MnSO4 + H2O + Cl2. → 5. FeSO4 + H2SO4 + Cl2 Fe2(SO4)3 + HCl. →

Section B (40 Marks) (Answer Any Four Questions)

Question 2

The apparatus above in set to obtain chlorine gas in the laboratory. a) i)Name the solution ‘A’ added through the thistle funnel. [1] ii) State the function of the substance ‘B’ placed in the round bottomed flask. [1] iii) What is purpose of arrangement of Thistle funnel in such a way that it is placed dipping

below the level of the acid in the flask? [1] iv) Give a balanced equation for the above method of preparation of chlorine. [2] v) How is the gas purified? [1] vi) Why is the chlorine gas collected in the jar by upward displacement of air? [1] vii) How is the identification of Cl2 gas done? [1] viii) In the above laboratory preparation substance B acts as an oxidizing agent and not a

catalyst. Explain ? [2]

Question 3

1. Differentiate between Dalton’s atomic theory and Modern atomic theory. [2] 2. Give the names of an acid salt found in “Health Salts”. [1] 3. Write the equation for the following and state if it is a decomposition reaction.“the

reaction when ammonia is passed over heated copper oxide”. [2] 4. Give reason: In blast furnace for the manufacture of cast iron from its ore oxygen gas is preferred than air to oxidize the charge. Why? [1] 5. Define the term Allotropy? Name the two forms of allotropes of sulphur. [2]

6. Starting from sodium hydroxide solution, how would you prepare sodium hydrogen carbonate. Write the appropriate equations. [2]

Question 4 a) Study the reaction scheme below and then answer (i) (ii) and (iii) which follow:

Marble Calcium oxide + Gas A → ↓ (+ little water) Solid B ↓ (+ excess water and filter) Solution C i) Give the chemical name and formula of a) marble b) gas A c) Solid B. [6]

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ii) What would you expect to see when drops of water are added to solid calcium oxide.[1] iii) a) Rewrite the following sentences filling in the blanks. [2] Solution ‘C’ is normally called ____ when gas ‘A’ is babbled through ‘C’,a white precipitate

of ____ is formed. b) On bubbling excess of gas A through the resulting suspension, the white precipitate

dissolves and then reappears on boiling. Suggest an explanation for these observations. [1]

Question 5

a) The electronic configuration [structure] of fluorine can be written as 2,7. In a similar way give the electronic configuration of i) aluminium ii) Phosphorus. [4]

b) Copy and complete the following table relating to the atomic structure of some elements.[6]

Element AtomicNumber

MassNumber

No. ofProtons

No. ofNeutrons

No. ofElectrons

Beryllium 4 9

Fluorine 9 10

Sodium 12 11

Aluminium 27 13

Phosphorus 31 15

Question 6 1. Express kelvin zero in oC. [1] 2. Fill in the blanks with correct word, from the words in bracket [5] a) If the temperature of a fixed mass of a gas is kept constant and the pressure is increased,

the volume correspondingly _____ [increases/decreases]. b) If the pressure of a fixed mass of a gas is kept constant and the temperature is increased,

the volume correspondingly ____[increases/decreases]. c) 1dm3 of a gas is equal to ____[1 litre / 100 ml / 100CC] d)All the temperatures on the kelvin scale are in ____figures [negative/positive]. e)At 273oC the volume of a gas is theoretically ____[272CC /0CC /274CC]. 3. Calculate the final volume of a gas, if the pressure of the gas, originally at S.T.P is doubled

and its temperature is tripled. [4]

Question 7 a) Name a homogenous mixture of : i) a liquid and a solid ii) two liquids. [2] b) What is the valency of Nitrogen in i) NO ii) N2O iii) NO2. [3] c) State which of the following formulas of compounds A to D are incorrect if incorrect write

the correct formula . A : (NH4)3SO4 B : KCr2O7 C : NaCO3 D : Ca2(PO4)3 . [2] d) Select the correct method from the method in bracket for separation of each mixture [3] i) Iodine and potassium chloride [sedimentation, filteration, sublimation, distillation]. ii) KNO3 from aqueous solution of KNO3 [solvent extraction, evaporation, filteration,

decantation] iii) Ammonia and hydrogen chloride [Liquefaction, solvent-water, diffusion,

boiling]. @@@

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Chemistry Paper 17 Section A (40 Marks)

(Answer All The Questions)

Question 1

I) Name the following: [5] a) An ammonium salt which liberates nitrogen on thermal decomposition. b) A carbon allotrope used in a) lead pencils b) Arc lamps c) The gas liberated at the cathode during electrolysis of acidified water. d) The non metal which combines with chlorine to give two chlorides. e) A gaseous hydrocarbon obtained from carbon.

II) Identify A,B & C and give balanced chemical equations: [5] a) A white substance ‘A’ which leaves an amphoteric oxide ‘B’ as a residue and evolves a

gas ‘C’ which turns lime water milky. b) An efflorescent substance ‘A’ which leaves a residue ‘B’ having the same colour as the

substance and evolves a gas ‘C’ which changes the colour of cobalt chloride paper.

III) Give balanced equations for the following conversions: [5] a) Red lead to litharge. b) Hydrated copper sulphate to sulphur di oxide. c) Ammonium di chromate to nitrogen. d) Mercuric oxide to mercury. e) Zinc nitrate to nitrogen di oxide.

IV) Select the correct answers: [5] a) The valency of copper in CuCl2 is ____[1+/2+/3+]. b) The maximum number of electrons in any shell of an atom is represented by ___

[n2/4n/2n2]. The maximum number of electrons in the M shell is _____ [2/32/18/8]. c) Isotopes of chlorine have the same ____, but different number of ____ [atomic

number/mass number/neutrons/protons/electrons]. d) Nitrogen reacts with hydrogen to give ammonia under specific conditions with use of

catalyst ___ [Platinum/Vanadium pentoxide/iron].

V) State your observations for each of the following:- [10] 1. Moist blue litmus paper is introduced into a jar of chloride. 2. When a glowing splinter is introduced into a jar of Mercury (II) oxide. 3. Glass rod dipped in HCl is introduced in a jar of ammonia. 4. When a blue vitriol is heated strongly. 5. Magnesium ribbon is treated with concentrated H2So4.

VI) Give reasons:- [10] 1. Diamond does not leave a mark on paper but graphite does. 2. Lime water cannot be used as a test to distinguish between CO2 and SO2 gas. 3. Hydrogen shows both electropositive and electronegative character. 4. Food containers are tin plated and not galvanized for rust prevention. 5. The halogen, chlorine of group VII A displaces bromine from potassium bromide.

Section B (40 Marks)

(Answer Any Four Questions)

Question 2 a) State two industrial uses of carbon di oxide. State the composition of i) dry ice ii) baking

powder iii) aerated soft drinks. [2] b) Give reasons for the following : Though carbon monoxide and chlorine are very poisonous

gas, carbon monoxide is a more dangerous gas than chlorine. [3]

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c) 1. State two processes which maintain the level of carbon di oxide in the atmosphere. 2. How will you separate CO2 and CO from their mixture. [5]

Question 3 1. Write the complete symbol for. [10] i) the nucleus with atomic numbers 26 and mass number 55. ii) the nucleus with atomic numbers 4 and mass number 9. 2. There are 14 protons and 13 neutrons in the nucleus of an atom. What its mass number? 3. What is common in the isotopes of an element? 4. The atomic number of cation M2+ is 12. How many electrons are present in it? 5. Which isotope of H2 is called protium? 6. Which particles determine the mass of an atom? 7. Are electrons stationary in the stationary state of an atom? Give reason.

Question 4

1. Fill in the blanks: [10]

Ions

N3-

O2- F- Na+ Mg2+

Atomic Number ___ 8 ___ 11 12

Nuclear Charge 10 ___ 10 ___ ___

2. Out of Li+, Be2+ and B3+ ions, which has the smallest ionic radius and why? 3. Arrange the following in decreasing atomic size. Mg2+, Al3+, Na+.

4. Which of the following pairs of elements has higher electron affinity? a) N or O b) F or Cl c) Be or B. Explain your answers.

Question 5 1. Give reason for the following:- [5] i) On boiling water loses its taste. ii) Common salt turns moist on exposure to air. iii) Dilute HNO3 is not used in the preparation of H2 from metals. iv) Diamond is used in precision instrument. v) Wood charcoal absorbs large volumes of gases units outer surface. 2. From the elements of group IVA of the periodic table select the properties from A to E

which does not pertain to the element carbon. IVA Group C A: is least electronegative. [5] Si B: reacts with concentrated HCl and dilute NaOH. Ge C: forms an acidic and a neutral oxide Sn D: exhibits valency of +2 and +4. Pb E: combines with halogens to give tetra halides. Question 6

1. Match each reaction given in list I with the condition required for each reaction present in List II [5]

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List I List II 1. N2+O2 2NO A: Room temperature around 150oC. 2. CaC2+N2 CaCN2+C → B: Burning substance above a dull red heat.

3. N2+3H2 2NH3 C: Room temperature around 1000oC.

4.2NH3+CO2 (NH2)2CO+H2O → D: Room temperature around 800oC. 5. 3Mg + N2 Mg3N2 → E: Electric ax - 3000oC. F: Promotor - molybdenum. 2. Show the formation of the following compounds: [4] i) Calcium oxide. ii) Ammonia. 3. Give the 2 variable valency of copper. [1]

Question 7 a) The apparatus show the industrial preparation of O2 from air. [8] 1. Identify the labelled chambers A, B, C & D in the diagram. 2. Name the principle adopted in the synthesis of O2 in this method. 3. Write the composition of liquified air. 4. Mention the temperature and pressure involved in this synthesis. 5. Why is the dried O2 stored in steel cylinders under pressure. b) Name the process in which nitric acid and sulphuric acid manufactured. [2]

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Chemistry Paper 18 Section A (40 Marks)

(Answer All The Questions)

Question 1

a) Ammonium chloride and excess of Ammonium hydroxide is added to the solution containing ions in List I, List II gives the details of the precipitate obtained. Copy and complete the table below to match the ions i, ii, iii, iv, v with their precipitates A, B, C, D, E. [5]

List I List II 1) Zn2+ A: White precipitate turns brown slowly. 2) Mn2+ B: gelatinous 3) Al3+ C: dirty green participate. 4) Fe2+ D: reddish brown participate. 5) Fe3+ E: White precipitate with (H2S).

Ions Precipitates 1 2 3 4 5 b) In each of the statements given below supply the word/s to make each incorrect

statement a correct statement. Write the correct statement with replaced word/s in full. [5]

i) Chlorine gas turns moist red litmus paper blue. ii) A Chemical reaction which takes place when an element has replaced another

element in a compound is called double decomposition reaction. iii) When chlorine gas reacts with potassium bromide salt, oxidation of potassium

chloride takes place. iv) Condensation is a process of change from liquid state to a gaseous state. v) As per the modern periodic table “The physical & chemical properties of elements

are periodic function of their atomic mass.

c) From among the gases - A)CO2 B)SO2 C) NH3 D) water vapour E)H2S select one in each case to which of the following description could apply. [5]

i) Turns moist red litmus paper blue. ii) Turns limewater milky and blue litmus paper slightly pink. iii) Turns cobalt chloride paper from blue to pink. iv) Turns lead acetate paper from white to silvery black. v) Turns acidified KMnO4 from pink to clear colourless.

d) What do observe when : [5]

i) Copper nitrate solution is heated strongly. ii) Ammonium di chromate crystals are heated strongly. iii) Concentrated HCl acid rod is exposed to a fumes of Ammonia. iv) A burning Magnesium wire is introduced into a jar of Nitrogen. v) Chlorine gas is passed through moist coloured flowers.

e) Give reasons for the following: [5] i) Chlorine shows similarities in properties with bromine and iodine present in group

VIIA of the periodic table.

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ii) The amount of carbon di oxide liberated in the same when equal amounts of diamond and graphite are burnt.

iii) Chlorine water decomposes in diffused sunlight. iv) During vulcanisation of rubber the soft sticky rubber turns into a hard mass. v) Atoms of elements other than noble gases are assumed to have unstable electronic

configuration.

f) Name the following: [5] i) Name the electrons which take part in the bond formation. ii) Name the type of elements that take part in the ionic bond formation. iii) Name the molecules which listed have covalent bonds a) CaCl2 b) NH3 c) MgO

d) PCl5. iv) Name one confirmatory test for Ammonium radical (Characteristic reaction)

g) Write balanced chemical equation for the following: [5] i) Thermal decomposition of calcium carbonate. ii) Ammonia with carbon di oxide. iii) Sulphur with chlorine gas. iv) Formic acid in the presence of dehydrating agent. v) When carbon monoxide is heated with sodium hydroxide.

h) Identify the correct nitrate from the following, to match the following description:- [5] i) Ag(NO3)2 ii) Cu(NO3)2 iii)NH4NO3 iv) Pb(NO3)2 v) KNO3 i) Is colourless, a constituent of gun powder and leaves a pale yellow residue on

heating. ii) Is colourless, on heating leaves no residue and evolves two neutral gaseous

products. iii) Is colourless and leaves a coloured residue on heating, the residue reacts with an

acid but not with a base to give salt and water. iv) Is white corrosive and on heating forms a silver mirror on heating. v) Is colourless, decrepitates and on heating leaves a yellow residue which fuses with

the glass.

Section B (40 Marks) (Answer Any Four Questions)

Question 2 1. Answer the following questions. [6] i) Write the general electronic configuration of elements of group 4. ii) Name the first and last element in group 4. iii) What is the nature of germanium? iv) Out of diamond and graphite, which is conducting in nature? v) Do Lead pencils contain lead in them? vi) What do bucky balls represent? 2. Represent a co-ordinate bond for i) NH4+ ions and ii) H3O+ ion. [4]

Question 3 1. Write the oxidation number of K atom in the following well known oxidants: [3] i) KMnO4ii)K2Cr2O7 iii)KClO4

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2. Which reactant is reducing agent in the following reaction? Cu2+ +H 2(g) Cu +

2H+ [1] →

3. What happens to positive valency in oxidation? [1] 4. A compound of carbon, hydrogen, and oxygen contains these elements in the ratio

by mass 6:1:4. Calculate its empirical formula. If its vapour density is 22. Calculate its molecular formula. [5]

Question 4 1. Starting from sulphur, how are the following prepared i) pure sulphur dioxide ii)

sodium sulphite [2] 2. Explanation with equations what happens when [4] i) SO2 is passed through acidified KMnO4 solution. ii) Concentrated H2SO4 is added to potassium iodide crystals. 3. In which of the following reactions does H2SO4 acts as i) an acid ii) a dehydrating

agent iii) an oxidising agent. a) Sugar. b) Sulphur is converted into sulphur di oxide. c) SO2 is liberated with copper. d) Sodium sulphate is formed with sodium hydroxide e) CO is liberated with oxalic acid. [4]

Question 5 1. Match the following : - [5] A B i) Sulphate a) Lime water. ii) Iodide b) Barium Chloride. iii) Carbonate c) Concentrated H2SO4 (Cold) iv) Nitrate d) Silver nitrate. v) Chloride e) Potassium chromate. f) concentrated H2SO4 (Hot) 2) Rewrite the following as directed :- [5] i) Cl, , [Arrange in increasing size] Cl − Cl +

ii) Mg, Na, Na+, Mg2+, Al [ which has largest size] iii) , Na+, F-, , Mg2+ [ Arrange in order of increasing order]. 3N − 2O −

iv) Li, Na, K [Arrange elements in decreasing electronegative affinities ]. v) Na, P, Cl [Which has maximum ionisation energy value].

v) Na, P, Cl [Which has maximum ionisation energy value].

Question 6 1. Identify the substance in the process and give a balanced equation for the following. [6] a) A white solid ‘A’ which evolves two colourless gases on heating B + C which on

cooling combine and condense on the cooler parts of the test tube. b) A coloured substance ‘A’ on heating decomposes violently leaving a coloured

residue ‘B’ and evolving two neutral gas C + D one of which is un reactive or inert in nature.

2. Complete the table given below:- [4] a) Addition of dilute H2SO4 to KHCO3, name the residue obtained ___.

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b) Addition of dilute H2SO4 to Zn, Test for gas evolved ___. c) Heat on sodium chloride. Colour imparted to flame during flame test ____. d) Flame test for calcium chloride. Acid used for flame test ____.

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Chemistry Paper 19 Section A (40 Marks)

(Answer All The Questions)

Question 1 1. Name the method of preventing rusting either by using metallic or non metallic

oxides in each case, when article on which coating is applied. [5] a) Domestic iron articles.b) Exposed and moving iron parts of Tools and machinery. c) Iron articles which are generally exposed to heavy moisture. d) Iron articles generally for edible applications. e) Specialized iron articles generally requiring strong resistance to rusting. 2. Mention the compound of sulphur used in industries. [5] a) Explosive industry. b) paper industry. c) photography industry. d) Match industry (safety match). e) textile industry. 3. Give the balanced chemical equations and temperature condition for reaction when

Nitrogen gas reacts with [5] a) Oxygen. b) Hydrogen. c) Calcium carbide. d) Magnesium. e) Aluminium. 4. Identify the type of reaction and state whether it is oxidised or reduced product :[5] Reactions : oxidation, reduction, redox.

2 2 2

2 2

2 2

2 2

4 2 4 3

) 2 2 3 .

) .) 2 .) 2 .) 2 ( ) .

a H S SO H O S

b CuO H Cu H Ol H S HCl S

d Cl H S S HCle FeSO Fe SO

+ → +

+ → ++ → ++ → +

→

c C

5. Name these elements and also predict the family to which they belong i.e a) An

alkali metal b)Halogens c) Alkaline earth metal d) Transition metal e) Noble gases. [5]

Atomic number of element

Name of element Family of elements.

1) 9 2) 19 3) 4 4) 18 5) 24

6. Give reasons for the following: [6] a) Why are tyres of automobiles inflated to lesser pressure in summer than in winter? b) The size of the weather balloon becomes large and larger as it ascends up into

high attitude. Explain. c) Out of dry air and wet air, which is heavier? 7. Here are some examples of mixtures name the method of separation [4] a) Chalk powder + water. b) Nacl in sea water. c) methyl alcohol + ethyl alcohol. d) Iron filings and sand.

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8. Fill in the blanks with the correct word form the words in brackets: [5] a) A symbol represent a short form of an _____[atom / element / molecule]. b) Aurum is the Latin name for the metal ____[gold / lead / iron / silver]. c) A chemical equation is a short hand form for a ___[physical / chemical / change]. d) All chemical equations must be balanced to comply with ____[Avogadro’s / law

of conservation of matter / Gay lussac’s law] e)Variable valency is exhibited, since electro negetives are lost from an element from

the __[valence / penaltimate] shells.

Section B (40 Marks) (Answer Any Four Questions)

Question 2 1. NH4OH + HCl NH4Cl + H2O [5] →

A B a) What are A and B called as in a chemical equation? b) What does arrow indicates. c) Define the terms A & B. d) Name the substances in L.H.S and R.H.S of a chemical equation. 2. Give reasons for the following reactions. [5]

2 2o

2 2

o3000 Ca) 2 .

Heat upto 3000 C is required to form Nitric oxide.Sun lightb) 2

Light energy is required to form hydrogen chloride gas.

N O NO

H Cl HCl

+ ⎯⎯⎯⎯⎯→

+ ⎯⎯⎯⎯⎯→

2 2 c) 2H 2 .electric currentO H⎯⎯⎯⎯⎯⎯⎯→ + 2O

acidified [anode] Electricity is passed through the reactants.

3 2 2

2 2 2

80d) 4NH 5 4 6 .Chemical reactions take place by use of a catalyst.

Sound energye) C 2 .Reaction proceeds only by absorption of sound energy.

opt CO NO H O

H C H

+ ⎯⎯⎯⎯⎯→ +

⎯⎯⎯⎯⎯⎯⎯→ +

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Question 3 [5] a)

a) Identify the terms ‘A’ ‘B’ ‘C’ & ‘D’ in the above diagram. b) What is the composition of soda lime D. c) What is your observation when the candle is lit in the apparatus. d) What is the conclusion that you draw from the above observation ? e) What is the whole apparatus set connected to ?

b) A student forgot to add the reaction mixture to the round bottomed flash at 27oC but put it on the flame. After a lapse of time, he realised his mistake. By using a pyrometer, he found that the temperature of the flask was 477oC. What fraction of air would have been expelled out? [5]

Question 4 1. State the correct product from the products A to E formed from each of the following

reactions 1 to 5. A) Copper [II] chloride B)Sodium chlorate C) Nitrogen D) Phosphorus penta

chloride. E) Sulphur monochloride. 1. P4 + 10Cl2 2. 2S +Cl2 3. NH3 [excess] + 3Cl2 → → →

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4. 6 NaOH + 3Cl2 5. Cu + Cl2 [5]

→ →

2. An atom X has 2,8,7 electrons in its orbit. It combines with Y having 1 electron in its orbit. i) What type of bond will be formed between X and Y?

ii) Write the formula of the compound formed. iii) It is soluble in water. iv) Does the compound conducts electricity or not. [5] Question 5 1. Give a chemical test to distinguish between the following. [10] a) Carbonate and bicarbonate b) Chlorine and bromine. 2. Using a platinum wire, concentrated HCl and a flame. (Bunsen burner). How would

youdistinguish between the three salts i.e, potassium chloride, barium chloride, calcium chloride. Explain in brief the method used for the same.

Question 6 1. In the manufacture of ammonia from Haber’s process. [10] i) How is Nitrogen gas obtained. ii) Name the process from which Hydrogen gas is obtained. iii) Name the catalyst and promoter used in this reaction. iv) Name the type of reaction whether it is reversible or irreversible. Exothermic or

endothermic. v) Write a balanced chemical equation depicting all the conditions in this reaction.

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Chemistry Paper 20 Section A (40 Marks)

(Answer All The Questions)

Question 1 I. Define the following terms :- a) i) Absorption. ii) Occlusion. iii)Photosynthesis iv) Vulcanization. v) Activity series. vi) Hydrogenation. [6] b) What is meant by “Available chlorine”? Give equation. [2] c)When BaSO4 salt is added to BaCl2 solution, it turns to form a curdy white precipitate. To

the precipitate if dilute HCl is added it does not disappear. Why? Give an equation. [2]

II. State your observations and write equation for the reaction. [6] a) i) Ammonium di chromate crystals. ii) Hypochlorous acid is subjected to

diffused sun light. iii) Foam type fire extinguisher hits on the floor. b)Differentiate between [4] i) Valency and valence electron. ii) Chemical formula and chemical change. III. Identify and explain the process involved in industrial preparations

of i) Hydrogen ii) Nitrogen and oxygen iii) Sulphur. [3+4+3] IV. Select the correct answer from the bracket. [10] i) Which metal among the following dissolves in both acids and alkalies? a) Mg b) Al c) Fe d) Cu. ii) The element whose outermost electron is least securely held is a) Al b) Mg c) Fe d) Na. iii) The element which does not import any colour to the bunsen flame is a) Na b) Cu c) Al d) Ca. iv) Rusting of iron involves the formation of a) Hydrated ferrous oxide b) hydrated ferric oxide. c) Ferroso ferric oxide d)

ferrous hydroxide. v) The metal which does not give hydrogen on treatment with dilute HCl is a) Fe b)Cu c) Al d) Mg. vi) The most electro positive element among the following is a) Cu b) Al c) Na d) Fe. vii) Galvanised iron is prepared from coating iron with a) Chromium b) Nickel c) Copper d) Zinc. viii) Iron belongs to the elements of a) s-block b) d-block c) f-block d) p-block. ix) Point out the double salt among the following. a) Mohr’s salt b) blue vitriol c) green vitriol d) cuprammonium sulphate. x) Which of the following is the weakest base? a) NaOH b) Ca(OH)2 c) KOH d) Cu(OH)2.

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Section B (40 Marks) (Answer Any Four Questions)

Question 2

a) Show the electron dot diagram for the formation of following compounds & also state the type of bond formed in each case.

i) Magnesium oxide. ii) Methane. iii) Ammonia. b) Electrovalent compounds have light melting and boiling points. Why? [10] Question 3 a) Answer the following questions: 1. What is vertical column in the periodic table called? 2. What is the basis of mendeleev’s periodic table? 3. What is periodicity? 4. How many groups are there in the periodic table? 5. How many elements are there in the fourth period of the periodic table? 6. Which of the following in representative element? Na, Ce, Cr, Cu. 7. Which of the following is a transition element? C, K, Kr, Fe. 8. Which of the following belong to the lanthanide group of elements? Ti, Ce, Mn,

U. 9. What is the common feature of ions : Na+, Mg2+, Al3+. 10.Which of the following has the largest radius? N3-, O2-, F-. [10] Question 4 a) For the formulaes written give conventional name and the oxidation number of N in

each formula.(Conventional Name : Nitrogen pentoxide, Nitric oxide, Nitrogen sesquioxide, Nitrous oxide, Nitrogen di oxide).

1. N2O. 2. NO. 3. N2O3. 4. NO2. 5. N2O5. [6] b) In the Laboratory preparation of Hydrogen, the following wash bottles are used to

purify the gas. Match the wash bottles and U-tube used for this purposes. [3] List A List B a) wash bottle

Containing AgNO3 solution. i) Moisture.

b) wash bottle containing Pb(NO3)2 solution.

ii) NO2, CO2, SO2.

c) wash bottle iii) H2S. containing KOH solution.

d) U-Tube iv) AsH3, PH3. containing CaCl2 (anhydrous).

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c) Give reason: Lead cannot be used in the preparation of Hydrogen using dilute acids. [1]

Question 5 a) Answer the following 1) Name an acid-base indicator. 2) What is the function of an indicator in a titration? 3) What colour change is observed when an acid solution containing methyl red is neutralized by a

base? 4) Which indicator shows a pink colour in basic medium and is colourless in acid

medium? 5) Give an example of a monobasic acid. b) A balloon contains 5.41 dm3 of helium at 24oC and 101.5 kpa suppose the gas in the

balloon is heated to 35oC. What is the volume of the gas if the new pressure is 102.8kpa. [10]

Question 6 a) [8]

The apparatus shows to identify and test the products of burning candle. a) Identify

the labelled apparatus and chemicals in the diagram A.B.C.D. b) Give a chemical equation for the above reaction. c) What is the purpose of having chemical B in the ‘U’ tube. Give the chemical

equation and indicate the characteristic reaction. d) What is the significance of chemical ‘C’ in the conical flask. Give the possible

chemical equation. e) What is the inference that you draw from the above experiment. b) A colourless pungent gas ‘A’ when subjected to litmus test changes moist red litmus

to blue, Identify the gas ‘A’ and give one confirmatory test to support your answer. [2]

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Chemistry Paper 21 Section A (40 Marks)

(Answer All The Questions)

Question 1 I. Select the correct word from the words in bracket to complete each statements: [5] 1. The oily liquid obtained when excess of chlorine reacts with ammonia

___[Ammonium chloride/ Nitrogen trichloride). 2. The process of coating iron with zinc is known as ___. [galvanizing / greasing] 3. ____ [Na2O2/PbO2] is a peroxide. 4. In the reaction of Magnesium and Nitrogen, the valency of the Nitride radical in

the product formed is ____ [+3,-3] 5. The volatile product of destructive distillation of wood is ____[wood charcoal/

wood tar]

II. Give reasons for the following: [5]

1. Wood charcoal floats on water. 2. Oxyhydrogen flame is used for cutting and welding metals. 3. Nitric acid in the dilute form is not used in the preparation of hydrogen from

metals. 4. Nitrogen gas manufactured is laboratory is not collected over air. 5. Extraction of sulphur from Frasch process is more advantageous than sicilian

process.

III. Match the following :- [5]

1. Sulphur a) Salt producer.

2. Chlorine b) Fixed air

3. Carbon di oxide c) Muriatic acid.

4. Hydrogen d) Brimstone.

5. Hydrochloricacid e) Inflammable gas.

IV. Name the following :- [5] 1. Spherical form of carbon containing 60 atoms in its molecular arrangement. 2. The process of heating any substance in the absence of air and distilling the

product. 3. The element in group V A, exists as diatomic gaseous molecule. 4. The inert gas used in filling electric bulbs. 5. The percentage of free oxygen in air. V Select and write the correct answer from the options given below. [5] 1. The dense white fumes obtained due to the reaction of chlorine gas and Ammonia

gas is ____. a) Ammonium chloride b) Ammonium hydroxide c) Ammonium carbonate d)

Ammonium nitrate. 2. Potassium chlorate and manganous di oxide is used in the laboratory preparation

of ____.

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a) Nitrogen b) Carbon c) Oxygen d)Hydrogen. 3. Discovery of the atomic nucleus by ___. a) J.J. Thomson b) Goldstein c) Rutherford d) James Chadwick. 4. The process by which ammonia is prepared in the industry is ____. a) Haber’s process b) Ostwald’s process c) Solvaej’s process d) None of these. 5. Elements having same atomic number but different atomic masses is called ___. a) Allotrophy b) Electro negativity c) Catenation d) Isotopes.

VI Write the balanced chemical equations for the following: [5] 1.Calcium carbide and Nitrogen. 2.Ammonia and carbon di oxide. 3. Sodium peroxide and water 4. Potassium permanganate and Hydrochloric acid. 5. Potassium bromide and chlorine.

VII Write ‘True’ or ‘False’ for the following statements: [5] 1. The molecular formula of chloroform is CCl4. 2. Bleaching action of sulphur di oxide takes place through oxidation. 3. Chlorofluro carbons are used in Refrigerating industry. 4. Carbon monoxide is collected by downward displacement of water. 5. Water is an universal solvent.

VIII Answer the following [5] 1. Define vulcanization. 2. Name the two crystalline allotropes of carbon.

3. What is carbon cycle. 4. Give the name of an acid salt found in “Health salts”. 5. What is the role of symbiotic bacteria in leguminous plants.

Section B (40 Marks) (Answer Any Four Questions)

Question 2 1. Complete the following [10]

Group 1 2 13 14 15 16 17 18

Secondperiod Li __ B C __ o __ __

Electronicconfiguration __ 2.2 __ __ 2.5 __ 2.7 2.8

Valenceelectron 1 __ 3 4 __ 5

Valency 1 __ __ __ __ __ 1 0

Question 3 1. In the laboratory preparation of Hydrogen by action of dilute HCl on zinc. i) Name the reactants taken in round bottomed flask. [1] ii) Give a balanced chemical equation for the above. [2] iii) How is the purification of H2 gas done name the impurities. [4] iv) Why is the gas collected by the downward displacement of water. [1] v) Give one precautions to be taken in preparation. [1] vi) What is granulated zinc. [1]

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Question 4 1. In the laboratory preparation of Nitrogen a) Why are reactants in the round bottom flask are in solution state. [1] b) N2 gas is generally not obtained in the laboratory by direct heating on ammonia

nitric alone. Why? [1] c) Chemical Nitrogen is free from ‘argon’ what does the statement explains. [2] d) Give a balanced chemical equation for the above preparation. [2] e) Why is the gas collected over water. [1]

2. What happens when ammonium dichromate crystals are heated ? [3] Question 5 1. Identify A white crystalline solid ‘A’ which decrepitates on heating leaving a

residue‘B’ which fuses with the glass and evolves two gases C & D one of which is coloured and acidic. Identify A, B, C, D give the possible chemical equation. Name the colour of the residue. [5]

2. A coloured mixed oxide ‘A’ which leaves a yellow amphoteric oxide ‘B’ residue and

evolves a neutral gas ‘C’ which rekindles a glowing splinter. Identify A, B, C. Give a chemical equation. What is the original colour of the salt. [5]

Question 6 1. Match the following [4] a. Na+ i) crimson red. b. Ca++ ii) lilac c. Ba++ iii) golden yellow d. k+ iv) brick red v) apple green Answer the following : - [6] 1) How many periods are there in the long form of periodic table? 2) How many groups are there in the long form of periodic table? 3) State modern periodic law. 4) Name the alkali metal, having the highest atomic radius and the least ionisation

energy. 5) Why electron affinity of fluorine is less than that of chlorine? 6) Which is the smallest among the following atoms Na, Al, Cl, s.

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Chemistry Paper 22 Section A (40 Marks)

(Answer All The Questions)

Question 1

I) Choose the letters A, B, C or D to match the descriptions (i) to (v) given below [5] i) Chromium is a) An alkali metal b) an alkaline earth metal c) a transition metal d) a lanthanide. ii) The allotropic form of sulphur which is insoluble in carbon di sulphide is a) Rhombic sulphur b) monochloric sulphur c) plastic sulphur d) none of these. iii) Which among the following has the highest ionisation energy. a) Na b) Mg c) K d)Rb. iv) On adding Cu turnings to a hot mixture of a salt and Concentrated H2SO4 brown

fumes are noticed. This is a test for a) Bromide b) Nitrate c) Sulphate d) Iodide. v) A salt on heating with water liberates colourless gas which turned lime water milky. The gas is a) Hydrogen chloride b) Hydrogen iodide c) carbon di oxide d) Sulphur di oxide.

II) Complete the following equations: [5] i) KHCO3 + H2SO4→ __ + __ +__. ii) CuSO4 __+ __ +__. → iii) CaCO3 + HCl __ +__ +__. iv) NH4Cl + NaNO2→ ___ +__ + __. → v) Fe2O3 + H2→ ___ +___ + ___.

III) What do you observe when : [5] i) Solid Ammonium chloride is heated in a test tube. ii) Potassium chloride with concentrated HCl paste is introduced to Bunsen flame. iii) Dilute hydrochloric acid is added to marble chips iv) Carbon di oxide gas reacts with milk of lime. v) Hydrocarbon burns in air.

IV) Name the following [5] i) The atom which does not have a neutron. ii) The scientist who proposed the nuclear theory. iii) The constituent particle present in the nucleus of an atom. iv) The most reactive non metal is. v) The element with atomic number 36 belongs to which block in the periodic table.

V) Give one word/ term for the following:- [5] i) Distribution of electrons. ii) Electrons present in last but one shell. iii)Chemical combinations of atoms involves. iv) Isotopes of chlorine having 20

neutrons. v) Number of lone pair of electrons in NH3 molecule.

VI) State one property of carbon (allotrops) [5] i) Due to which it is used in lead pencils. ii) Used as gem. iii) That makes it a good fuel. iv) production of black shoe polish. v) production of calcium carbide. VII) The types of chemical reactions are [5]

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a) Direct combination b) decomposition reaction. c) simple displacement d)double decomposition. State the type of chemical reaction that takes place for the following reactions:

i) Cl2 + Ca(OH)2 → CaOCl2 . H2O. ii) 2HgO →2Hg + O2. iii) KNO3+H2SO4 → HNO3 +KHSO4. iv) Cl2 + 2KBr → 2KCl + Br2. v) PbO2 +

SO2 → PbSO4. VIII) Select the correct method from the methods in brackets for separation of each

mixture. i) Hydrogen & Ammonia [Diffusion, Distillation]. [5]

ii) Methyl alcohol & ethyl alcohol [filtration, fractional distillation]. iii) Iron fillings and sulphur [solvent extraction, Boiling]. iv) Potassium nitrate + sodium chloride [ Fractional crystallisation, filtration] v) PbCl2 + water [Filtration, Evaporation].

Section B (40 Marks) (Answer Any Four Questions)

Question 2 a) For four elements A, B, C, D the following details are given below : [8]

Element MassNumber

Number ofNeutrons

A 40 20

B 19 10

C 20 10

D 23 12

State (i) the number of protons is A, B, C, D. (ii) state the nature of element A, B, C,

D. (iii) electronic configuration of D. (iv) the kind of bonding when D reacts with B. [2]

Question 3 a) Balance the following equations : [5] i) AgOH→ Ag + H2O +O2. ii) ZnS + O2 ZnO + SO2. → iii) Pb(NO3)2 PbO + NO2 + O2. iv) Fe + H2O→ Fe3O4 + H2. v) Mg3N2 + H2O Mg(OH)2 + NH3. → b) i) State 1. Boyle’s law 2. Charle’s law. [2] ii) What is absolute zero? [1] iii) Carbon di oxide occupies a volume of 512 cm3 at stp. Find its volume at 27oC

and 720 mm of Hg. [2] Question 4 a) Define the terms [3]

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(i) oxidation. (ii) reduction. (iii) redox reaction. b) State one significant observation when - [3] i) Chlorine gas is exposed to starch iodide paper. ii) Chlorine gas is exposed to moist blue litmus paper iii) Chlorine gas is dissolved in water. c) Write balanced equations for the reactions of sulphur with [4] i) Sulphuric acid ii) carbon iii) Hydrogen iv) Iron. Question 5 a) Draw an electron dot diagram to show the formation of: [4] i) Nitrogen molecule ii) Methane. b) Hydrogen gas is a strong reducing agent. i) Give an experimental evidence to show this property (procedure). [3] ii) Give a chemical equation to support your answer. [1] iii) What is your conclusion to support the above experiment. [2] Question 6 a) Answer the following [5] i) What is Hydrogenation of coal? Give a reason for this property. ii) What is “bone black” or “ivory black”. iii) What is “nitrolim”. How is it prepared. b) Nitrogen finds application in the manufacture of: [5] a) High temperature thermometers. b) Tinned food products. c) As a refrigerant. d) By plants. Give one reason or property of Nitrogen involved in the above applications. Question 7 i) Explain a simple experiment to show the solubility of O2 in water [4] ii) Support your answer with an analogy or example. [2] iii) Give the temperatures for the following with respect to O2 [2]

(a) Liquefaction b) freezing point or boiling point. iv) What happens when phosphorus burns in air. Give the complete balanced

equation for the above reaction. [2] @@@