, Ni , & Fe , oxides as well as sulphides are formed byvbmv.ac.in/pdf/MCQ Chemistry Dept-min.pdfthe...

1. Out of Sn2+, Ni2+, & Fe3+, oxides as well as sulphides are formed by

(a) Sn2+& Ni2+ (b) Ni2+& Fe3+ (c) Sn+2& Fe3+ (d) All the above

2. Color of complexes is satisfactorily explain by

(a) Werner’s theory (b) Valence Bond Theory (c) Crystal field Theory (d) Ligand Field Theory

3. Which of the following system has maximum number of unpaired electrons?

(a) d6 (tetrahedral) (b) d9 (octahedral) (c) d7 (octahedral, high spin) (d) d4 (octahedral, low spin)

4. What is the oxidation state of Iron in Hemoglobin & Myoglobin Respectively?

(a) 3, 2 (b) 2, 2 (c) 2, 3 (d) 3, 3

5. During biological nitrogen fixation nitrifying bacteria converts

(a) NO3- to NH4+ (b) N2 to NH4+ (c) NH4+ to NO3- (d) NO3- to N2

6. Consider the following redox reaction: 2MnO4- + 3ClO3- + H2 4- + 2MnO2 + 2OH-

The reducing agent is (a) H2O (b) ClO3- (c) MnO2 (d) MnO4-

7. Vanadium metal, V2+, reacts spontaneously with Cd2+, but not with Ti2+. Based on these results, the

order of oxidizing agents, from strongest to weakest, is

(a) Cd2+, V2+, Ti2+ (b) V2+, Ti2+, Cd2+ (c) Ti2+, Cd2+, V2+ (d) Ti2+, V2+, Cd2+

8. How many NMR signals would be given by the compound (CH3)2CHCH2CH3?

(a) 3 (b) 4 (c) 5 (d) 2

9. Classical mechanics does not provide satisfactory explanation for the following

(a) Black Body radiation (b) Photoelectric Effect (c) Heat Capacities (d) All the above

10. A quantitative relationship between the energy absorbed and energy emitted by a body was put

forwarded by (a) Einstein (b) Kirchhoff (c) Hess (d) Fermi

11. Valence Bond Theory of chemical bonding was put forward initially by

(a) Heisenberg (b) Einstein (c) Heitler & Lodon (d) De-Broglie

12. The Raman & IR spectra can tell us whether

(a) a molecule is linear or non-linear (b) a molecule is symmetrical or asymmetrical

(c) neither of these (d) both of the these

13. In the Raman Spectra, the middle line is called as

(a) Raman Line (b) Rayleigh Line (c) Functional Group Line (d) None of these

14. A molecule reacted or formed per photon of light absorbed is called

(a) Yield of reaction (b) Quantum of reaction (c) Quantum yield (d) Quantum Productivity

15. The light emitted in chemiluminescent reaction is also called as

(a) Cold light (b) Hot light (c) Bright light (d) none of these

16. Chiral molecule has

(a) no plane of symmetry (b) one plane of symmetry

(c) infinite plane of symmetry (d) one line of symmetry

17. An equimolar mixture of (+) and (-) Tartaric Acid is called as

(a) enantiomers

(b) optically active mixture

(c) racemic mixture

(d) asymmetric mixture

18. Optical activity is

(a) an additive property (b) constructive property (c) both of these (d) none of these

19. The substance which retain magnetic field when removed from the magnetic field is called

(a) paramagnetic (b) diamagnetic (c) ferrimagnetic (d) ferromagnetic

20. A diamagnetic substance is ……. by/in the magnetic field

(a) attracted (b) repelled (c) rotated (d) revolved

21. A liquid boils when vapor pressure becomes equal to

(a) One atmospheric pressure (b) zero (c) very high (d) very low

22. Freezing point depression is measured by

(a) Beckman’s Method (b) Rast Camphor Method (c) by Both (d) none of these

23. In one molal solution that contains 0.5 mole of a solute there is

(a) 1000gm of solvent (b) 1000ml of solvent (c) 500ml of solvent (d) 500gm of solvent

24. The law of relative lowering of vapor pressure was given by

(a) Van’t Hoff (b) Ostwald (c) Raoult (d) Henry

25. Which of the following is a colligative property?

(a) molar refractivity (b) optical rotation (c) depression in freezing point (d) viscosity

26. The number of moles of a solute per kilogram of the solvent is called

(a) formality (b) normality (c) molarity (d) molality

27. The study of depression in freezing point of a solution is called

(a) osmatic pressure (b) ebullioscopy (c) cryoscopy (d) none of these

28. Reaction intermediates of E1 reaction is

(a) carbocation (b) carbanion (c) carbine (d) free radical

29. In the reaction between 2-hydroxy-3-methyl butane with conc. H2SO4 at high temperature,

the number of alkene formed is (a) one (b) two (c) three (d) four

30. When propyne reacts with HgSO4/H2SO4, the product is

(a) Propane (b) Propanol (c) Propanal (d) Propanone

31. Which of the following reagents can be used for the test of unsaturation?

(a) dil KMnO4/OH- (b) conc KMnO4/OH- (c) KMnO4/H+ (d) Neutal KMnO4

32. Which among the following reagent will give nucleophilic addition with carbonyl compound?

(a) HCN (b) RMgX (c) Alcohol (d)HCl

33. With which compound Grignard Reagent gives 30- alcohol?

(a) Formaldehyde (b) Acetaldehyde (c) Acetone (d) Methylcynide

34.Which among the following reagents can be used for the test of carbonyl group in laboratory?

(a) NH2OH (b) NH2NH2 (c) NaSO3H (d) 2,4-DNPH

35. In which alkene anti-markovnikov’s rule can be used?

(a) Ethylene

(b) 2-Butene (c) Propene

(d) 2,3-dimethyl-2-butene

36. Which reagents give free radical addition with alkene?

(a) HBr (b) HCl (c)HI (d)HOH

37.Gattermann reaction is given by

(a) C6H6 (b) C6H5-CH3 (c) C6H5-Cl (d) All of these

38.Bendict solution is used for the detection of which compound present in urine?

(a) Urea (b) Urea Acetate (c) Steroid (d) Glucose

39. Which one of the following compounds will not give aldol?

(a) CH3CHO (b) CH3CH2CHO (c) CH3CH2COCH3 (d) C6H5CHO

40. Grignard Reagent does not give carbonyl compounds with

(a) CO2 (b) RCOCl (c) RCN (d) RCOOR

41. Benzaldehyde reacts with ammonia to form

(a) Banzaldehyde ammonia (b) Urotropine (c) Hydrobenzamide (d) Ammonium Chloride

42. First organic compound prepared in the laboratory was

(a) Acetic Acid (b) Urea (c) Formic acid (d) Methane

43. Tetravalency of carbon was proposed for the first time by

(a) Kekule (b) Couper (c) Kekule&Couper (d) van’t Hoff

44. Organic solids can be purified by

(a) steam distillation (b) Crystallization (c) Fractional distillation (d)Simple distillation

45. Which of the following compound sublimate on heating?

(a) p-Dichlorobenzene (b)Urea (c) Thiourea (d) Tartaric acid

46. Sodium extracts gives blood red coloration when treated with FeCl3 conform presence of

(a) Only nitrogen (b) Only sulphur (c) Only halogens (d) Both nitrogen &sulphur

47.Percentage of carbon in organic compound is determined by

(a) Duma’s method (b) Kjeldahl’s method (c) Carius method (d) Liebig method

48. A compound containing 80% carbon & 20% hydrogen is likely to be

(a) C6H6 (b) CH4 (c) C2H6 (d) C3H8

49. In sodium extract nitrogen is present as

(a) Sodamide (b) Sodium cyanide (c) Sodium nitrite (d) Sodium nitrate

50. Juice of sugarcane in factories is concentrated by

(a) Vacuum distillation (b) Steam distillation (c) Sublimation (d) Crystallization

51.Which of the following is photovoltaic cell?

(a) Barrier layer Cell (b) Bolometer (c)Golay Cell (d) Photo emissive cell

52. Which of the following compounds are transparent in UV region?

(a) Ethers (b) Alkyl amines (c) thioethers (d) All of them

53. The triatomic linear CO2 molecule has the following fundamental vibrations

(a) 4 (b) 2 (c) 3 (d) 6

54. Which of the following vibrational mode is Raman active in CO2 molecule?

(a) Symmetrical stretch (b) Asymmetrical stretch (c) Bending (d) All of these

55. How many types of hydrogens are present in the compound CH2BrCl?

(a) 2 (b) 1 (c)3 (d) None

56. In an electrochemical cell, electrons travel in which direction?

(a) from the anode to the cathode through the external circuit (b) from the anode to the cathode

through the porous cup (c) from the cathode to the anode through the external circuit (d) from the

cathode to the anode through the porous cup.

57. Which acid is present in lemon?

(a) malic acid (b) citric acid (c) lactic acid (d) tartaric acid

58. What among following is used to produce artificial rain?

(a) copper oxide (b) carbon monoxide (c) silver iodide (d) silver nitrate

59. Oil of vitriol is

(a) nitric acid (b) sulphuric acid (c) hydrochloric acid (d) phosphoric acid

60. Which of the following can be used in preparation of dynamite?

(a) glycerol (b) ethyl alcohol (c) methyl alcohol (d) glycol

61. What is a mixture of potassium nitrate powdered charcoal and sulphur called?

(a) paint (b) aluminium (c) brass (d) gun powder

62. How many atoms are in one mole of CH3OH?

(a) 6 (b) 6.0 x 1023 (c) 12.0 x 1023 (d) 3.6 x 1024

63. Which of the following compounds is a functional group isomer of ethanol?

(a) ethanol (b) acetic acid (c) diethyl ether (d) dimethyl ether

64. The synthetic element among the following is (a) Mo (b) U (c) Tc (d) Pa

65. Which of the following compounds displays optical isomerism?

(a) CH2(OH)-CH2(OH) (b) CH3-CHCl-COOH (c) CH2=CHCl(d) CHCl=CHCl.

66. Which of the following will undergo an addition reaction with chlorine?

(a) CH3CH2CH2CH3 (b) CH3CH2CH=CHCH3 (c) C6H6 (d) CH3CH2COOH

67. Which of the following elements has the smallest atomic radius?

a) I b) B c) O d) Al

68. What is Calcium sulphate?

(a) epsom salt (b) blue vitriol(c) gypsum salt (d) potash alum 69. Para-xylene is the same as:

(a) 1,2-dimethylbenzene (b) 1,3-diethylbenzene (c) 1,3-dimethylbenzene (d) 1,4-dimethylbenzene

70. Which of the following formulas represents an alkene?

(a) CH3CH2CH3 (b) CH3CH3 (c) CH3CH2CHCH2 (d) CH3CH2Cl

71. How many unpaired electrons are there in a strong field iron (II) octahedral complex?

(a) 0 (b) 1 (c) 2 (d) 4

72. Some element groups of the periodic table are more likely to contain elements that are gases than

other groups. Which of the following groups contains the greatest number of gaseous elements?

(a) IA (b) IIA (c) IVA (e) VIII (or 0)

73. Which of the following substances is the strongest reducing agent?

(a) Cl2 (b) Cl- (c) Br2 (d) Br-

74. Chlorine gas is prepared commercially by:

(a) electrolysis of carbon tetrachloride. (b) oxidation of chloride ion with F2(g).

(c) electrolysis of NaCl(aq). (d) oxidation of chloride ion with Br2(aq).

75. Which of the following has a pyramidal structure (molecular geometry)?

(a) CBr4 (b) PF3 (c) BF3 (d) OF2

76. What maximum mass of sulfuric acid can be produced from the sulfur contained in 100 kilograms of

iron pyrite that is 75.0% FeS2? (a) 84.4 kg (b) 123 kg (c) 136 kg (d) 144 kg

77. Which compound gives photochemical smog a brownish color?

(a) NO (b) HNO2 (c) NO2 (d) N2O4

78. What is the major mineral present in phosphate rock?

(a) Ca3(PO4)2 (b) Na2HPO4 (c) Ca10(PO4)6F2 (d) NaH2PO4

79. In a surprisingly large number of their properties beryllium resembles aluminum, and boron

resembles silicon. Such a relationship is called:

(a) amphoterism (b) an allotropic relationship (c) a diagonal relationship

80. The most abundant metal in the earth's crust is:

(d) the periodic law

(a) Cu (b) Fe (c) Na (d) Al

81. The nitrate of which of the following cations would exhibit paramagnetism to the GREATEST

extent? (a) Co3+ (b) Cr3+ (c) Fe3+ (d) Mn3+

82. Which of the following combinations cannot produce a buffer solution?

(a) HNO2 and NaNO2 (b) HCN and NaCN (c) HClO4 and NaClO4 (d) NH3 and (NH4)2SO4

83. Which one of the following molecules has a dipole moment?

a) CS2 b) CHCl3 c) SF6 d) CCl4

84. Which one of the following is a strong electrolyte?

(a) H2O (b) KF (c) HF (d) HNO2

85. Which of the following weak acids ionizes to give the strongest conjugate base?

(a) HClO (b) CH3COOH (c) HF (d) HCN

86. The entropy will usually increase when

I. a molecule is broken into two or more smaller molecules.

II. a reaction occurs that results in an increase in the number of moles of gas.

III. a solid changes to a liquid. IV. a liquid changes to a gas.

(a) I only (b) II only

(c) III only

(d) I, II, III, and IV

87. Which statement is incorrect?

(a) At constant pressure, H = E + P V (b) The thermodynamic symbol for entropy is S.

(c) Gibbs free energy is a state function. (d) For an endothermic process, H is negative.

88. For a gas, which pair of variables is inversely proportional to each other (if all other conditions

remain constant)? (a) P, T (b) P, V (c) V, T (d) n, V

89. Which radioactive emanations have a charge of -1?

(a)neutrons (b) gamma rays (c) alpha particles (d) beta particles

90. Which of the following is classified as a metal?

(a) Ge (b) As (c) F (d) V

91. Which one of the following salts is insoluble in water?

(a) NH4Cl (b) Ca(NO3)2 (c) BaCO3 (d) Na2S

92.What kind of radiation will travel through an electric field on a pathway that remains unaffected by

the field? (a) a proton (b) a gamma ray (c)an electron (d) an alpha particle

93.The species that contains 24 protons, 26 neutrons and 22 electrons would be represented by the

symbol: (a) 50V3+ (b) 26Cr2+ (c) 50Cr2+ (d) 50Mn2+

94.Which of the following is an ionic hydride?

(a) PH3 (b) H2S (c) HI (d) KH

95.Which of the following is the most basic oxide?

(a) N2O3 (b) N2O5 (c) P4O6 (d) Bi2O5

96. Which property is generally characteristic of an organic compound?

(a) low melting point (b) high melting point (c) soluble in polar solvents (d) insoluble in nonpolar

solvents

97. Which radioactive isotope is used in geological dating?

(a)uranium-238 (b)iodine-131 (c)cobalt-60 (d)technetium-99

98. Which nuclide is a radioisotope used in the study of organic reaction mechanisms?

(a) carbon-12 (b) carbon-14 (c) uranium-235 (d) uranium-238

99. Which polymers occur naturally?

(a) Starch and nylon (b) starch and cellulose (c) protein and nylon

100. The products of the fermentation of sugar are ethanol and

(d) protein and plastic

(a) water (b) oxygen (c) carbon dioxide (d)sulfur dioxide

:

ssb: 11

:

ssb: 22

:

ssb: 33

:

ssb: 44

:

ssb: 55

:

ssb: 66

45. An adiabatic process is one in which

(a) Number of heat enters or leaves the gas

(b) Temperature of the gas changes

(c) The change in internal energy is equal to the mechanical workdone

46. The processes occurring in open system which permit the transfer of mass to

and from the system, are known as

(a) Flow process

(b)non-flow processes

(c) adiabatic processes

(d) none of these

47. Workdone in free expansion process is

(a) zero

(b)minimum

(c)maximum

(d)positive

48.Which of the following is not property of the system

(a) Temperature

(b) Pressure

(c) Specific volume

(d) Heat

(e) None of these

:

ssb: 77

Answer Key of Thermodynamics:-

(1)b (2) d (3)b (4) c (5) c (6)d (7)d (8)c (9) a (10)b (11)c (12)a (13)c (14)a (15)b

(16)d (17) b (18)c (19)c (20)c (21)b (22)b (23)c (24)b (25)c (26)d (27)d (28)b

(29)b (30)a (31) d (32)b (33)c (34)c (35)c (36)d (37)d (38)c (39)c (40)b (41)d

(42)a (43)a (44)a (45)d (46)a (47)a (48)d (49)e (50)e

:

ssb: 88

:

ssb: 99

:

ssb: 1100

Answer key of Gaseous State:-

(1) c (2) c (3) b (4) a (5)c (6) d (7)a (8)b (9) c (10) a (11) a (12)b (13)a (14) d

(15)c (16)e (17) c (18) d (19)a (20) a (21)a (22) b (23)a (24)a (25)c (26) d

(27)a (28) a (29)a (30) a (31) a (32) c (33) c (34) b (35) c (36)d (37) c(38)d

(39)d (40)b (41)a (42) a (43) c (44)b (45)b (46) a (47) d (48)a (49)a (50)b

VSEPR Theory

MULTIPLE CHOICE QUESTIONS

10.1 According to the VSEPR theory, the geometry of the SO3 molecule is:

M

A. pyramidal

B. tetrahedral

C. trigonal planar

D. distorted tetrahedron

E. square planar

Answer: C

10.2 The geometry of the SF4 molecule is

M

A. tetrahedral B. trigonal pyramidal C. trigonal planar D. square planar

E. distorted tetrahedron

Answer: E

10.3 Use VSEPR theory to predict the geometry of the PCl3 molecule.

M

A. linear B. bent C. trigonal planar D. trigonal pyramid E. tetrahedral

Answer: D

10.4 According to VSEPR theory the geometry of the PH3 molecule is best described as:

M

A. linear

B. trigonal planar

C. tetrahedral

D. bent

E. trigonal pyramidal

Answer: E

10.5 The geometry of the CS2 molecule is best described as:

E

A. linear

B. trigonal planar

C. tetrahedral

D. bent


Answer: A

174 CHAPTER 10: MOLECULAR GEOMETRY

10.6 The geometry of the ClF3 molecule is best described as:

M

A. distorted tetrahedron

B. trigonal planar

C. tetrahedral

D. T-shaped


Answer: D

10.7 According to the VSEPR theory, the geometry of the atoms in the carbonate ion,

M CO32 ─

is:

A. square planar

B. tetrahedral

C. pyramidal

D. trigonal planar

E. octahedral

Answer: D

10.8 According to the VSEPR theory, which one of the following species is linear?

E

A. H2S B. HCN C. BF3 D. H2CO E. SO2

Answer: B

10.9 According to VSEPR theory which one of the following molecules is trigonal

M bipyramidal?

A. SF4 B. XeF4 C. NF3 D. SF6 E. PF5

Answer: E

10.10 According to VSEPR theory which one of the following molecules is bent?

E

A. CO2 B. C2H2 C. SO2 D. BeCl2 E. KrF2

Answer: C

10.11 According to VSEPR theory, which one of the following molecules has a bent

M geometry?

A. Cl2O B. CO2 C. HCN D. CCl4 E. none of these

Answer: A

10.12 Which one of the following molecules has tetrahedral geometry?

E

A. XeF4 B. BF3 C. AsF5 D. CF4 E. NH3

Answer: D

CHAPTER 10: MOLECULAR GEOMETRY 175

10.13 According to VSEPR theory, which one of the following molecules has a

E tetrahedral geometry?

A. NH3 B. CCl4 C. CO2 D. SF4 E. PCl5

Answer: B

10.14 The bond angle in Cl2O is expected to be approximately:

M

A. 90 o

B. 109.5 o C. 120

o D. 145

o E. 180

o

Answer: B

10.15 The F ─ S ─ F bond angles in SF6 are:

H

A. 90 o

B. 109.5 o

C. 120 o

D. 180 o

E. 90 o and 180

o

Answer: E

10.16 The F ─ Cl ─ F bond angles in ClF3 are:

M

A. 90 o only

B. 109.5 o only

C. 120 o only

D. 180 o only

E. 90 o and 180

o

Answer: E

10.17 According to the VSEPR theory, the F ─ As ─ F bond angles in the AsF4─ ion are

M predicted to be:

A. 109.5o

B. 90o and 120

o

C. 180 o

D. <109.5o

E. >90o, >120

o, and <180

o

Answer: E

10.18 Which one of the following molecules is nonpolar?

M

A. NH3

B. OF2

C. CH3Cl

D. H2O

E. BeCl2

Answer: E


10.19 Complete the sentence. The PCl5 molecule has:

M

A. nonpolar bonds, and is a nonpolar molecule.

B. nonpolar bonds, but is a polar molecule.

C. polar bonds, and is a polar molecule.

D. polar bonds, but is a nonpolar molecule.

Answer: D

10.20 Which one of the following molecules has a dipole moment?

M

A. BeCl2

B. Br2

C. BF3

D. IBr

E. CO2

Answer: D

10.21 Which one of the following molecules has no dipole moment?

M

A. CO B. CH2Cl2 C. SO3 D. SO2 E. NH3

Answer: C

10.22 Which one of the following is a polar molecule?

M

A. PBr5

B. CCl4

C. BrF5

D. XeF2

E. XeF4

Answer: C

10.23 Predict the molecular geometry and polarity of the SO2 molecule.

M

A. linear, polar B. linear, nonpolar C. bent, polar D. bent, nonpolar

E. None of these is correct.

Answer: C

10.24 Predict the geometry and polarity of the CS2 molecule.

M

A. linear, polar B. linear, nonpolar C. tetrahedral, nonpolar

D. bent, nonpolar E. bent, polar

Answer: B


10.25 Indicate the type of hybrid orbitals used by the central atom in PCl3.

H

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: C

10.26 Indicate the type of hybrid orbitals used by the central atom in CCl4.

M

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: C

10.27 Indicate the type of hybrid orbitals used by the central atom in SF6.

H

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: E

10.28 What is the hybridization of the As atom in the AsF5 molecule?

M

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: D

10.29 What is the hybridization of the central atom in NO3─ ?

M

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: B

10.30 Which one of the following molecules has sp2 hybridization at the central atom?

M

A. SO2 B. N2O C. BeCl2 D. NF3 E. PF5

Answer: A

10.31 What is the hybridization of As in the AsF4─ ion?

M

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: D

10.32 What is the hybridization of the central atom in ClO3─ ?

H

A. sp B. sp2 C. sp

3 D. sp

3d E. sp

3d

2

Answer: C


10.33 Which of the following covalent species have the same geometries?

M

A. NH2─

and H2O

B. NH2─

and BeH2

C. H2O and BeH2

D. NH2─

, H2O, and BeH2

Answer: A

10.34 Which of the following molecules have the same geometries?

M

A. SF4 and CH4

B. CO2 and H2O

C. CO2 and BeH2

D. N2 O and NO2

Answer: C

10.35 Predict the molecular geometry of SO3.

M

A. trigonal planar B. trigonal pyramidal C. tetrahedral D. T-shaped

Answer: A

10.36 Which pair is geometrically similar?

M

A. SO2 and CO2

B. CO2 and OF2

C. PH3 and BF3

D. SO2 and O3

Answer: D

10.37 The fact that BCl3 is a planar molecule while NCl3

is pyramidal can be explained

M several different ways. Which is the best rationalization?

A. Nitrogen is more electronegative than boron.

B. The nitrogen atom in NCl3 has a lone pair of electrons whereas

the boron atom in BCl3 does not.

C. The nitrogen atom is smaller than the boron atom.

D. The boron atom in BCl3 is sp

3 hybridized, while the

nitrogen atom in NCl3 is sp2 hybridized.

Answer: B


10.38 NH3 (pyramidal geometry) reacts with BF3 (planar geometry) to form the

M addition compound, H3NBF3. What is the geometry around the nitrogen and boron centers in the addition

compound?

A. Both centers are tetrahedral.

B. Nitrogen–tetrahedral and boron–linear.

C. Nitrogen–pyramidal and boron–planar.

D. Nitrogen–planar and boron–pyramidal.

Answer: A

10.39 Which geometry is associated with an sp hybridized atom?

E

A. pyramidal C. trigonal planar

B. tetrahedral D. linear

Answer: D

10.40 The geometry for SeF3+ is:

M

A. trigonal pyramidal.

B. square planar.

C. tetrahedral.

D. rectangular planar

Answer: A

10.41 Which of the following covalent species is planar?

E

A. NH3 B. SO3 2 ─

C. CO3 2 ─

D. H3O+

Answer: C

10.42 Which of the following molecules is linear?

E

A. H2O B. NH3 C. NO2 D. CO2 E. H2S

Answer: D

10.43 Which of the following statements is true of methane?

E

A. It is a tetrahedral molecule.

B. It contains single and double bonds.

C. It contains 80% hydrogen by weight.

D. It does not occur in nature.

E. It is a polar molecule.

Answer: A


10.44 The ammonium ion is symmetrical, with the nitrogen at the center of a

E tetrahedron of four equivalent hydrogens. The N atom in the ion may best be described as using:

A. only sp3 hybridized orbitals.

B. only sp2 hybridized orbitals.

C. sp2 and s orbitals.

D. sp2 and p orbitals.

Answer: A

10.45 Which type of hybrid orbital is used by carbon in CO2?

E

A. sp B. sp2 C. sp

3 D. dsp

3

Answer: A

10.46 Which is the largest bond angle?

M

A. angle O–S–O in SO4 2 ─

B. angle Cl–C–Cl in HCCl3

C. angle F–Be–F in BeF2

D. angle H–O–H in H2O

Answer: C

10.47 In Molecular Orbital theory, the bond order =

E

A. the total number of valence electrons available for bonding.

B. (the number of electrons in bonding MOs) + (the number of electrons in antibonding MOs).

C. (the number of electrons in bonding MOs) - (the number of electrons in antibonding MOs).

D. (number of electrons in bonding MOs) - (number of electrons in antibonding MOs)

2

E. (number of electrons in bonding MOs) + (number of electrons in antibonding MOs)

2

10.48 What is the bond order of N2, for which the MO electron configuration is: σ2s2σ*2s

2π2py2π2pz

2σ2px2

E

A. 1

B. 2

C. 3

D. 4

E. none of these

Answer: C


10.49 Which of the following substances is an example of a homonuclear diatomic molecule?

E

A. O3

B. NO

C. He

D. F2

E. NH3

Answer: D

SHORT ANSWER QUESTIONS

10.50 Use VSEPR theory to predict the molecular geometries of

H

a. H3O+ (hydronium ion) ___________________

b. CO32─

___________________

c. SF4 (sulfur tetrafluoride) ___________________

Answer: a. trigonal pyramid b. trigonal planar c. distorted tetrahedron

10.51 Use VSEPR theory to explain why the water molecule is bent, rather than linear.

E

Answer: The central oxygen atom must distribute 4 pairs of electrons around itself. Two are lone pairs.

10.52 Using periodic trends arrange the following molecules in order of increasing dipole

M moment: NH3, PH3, AsH3.

Answer: AsH3 < PH3 < NH3

10.53 Explain why CO2 is nonpolar, but OCS is polar.

M

Answer: In CO2, the two bond moments point in opposite directions and are of equal magnitude. Therefore

they cancel. But in OCS, even though the two bond moments point in opposite directions, they are not of the

same magnitude and so do not cancel.

10.54 The N ─ N ─ H bond angles in hydrazine N2H4 are 112 o. What is the

M hybridization of the nitrogen orbitals predicted by valence bond theory?

Answer: sp2

10.55 Indicate the number of π - bonds in each of these molecules.

E

a. C2H4 ________

b. C2H6 ________

c. N2H2 ________

Answer: a. 1 b. 0 c. 1


10.56 a. According to the VSEPR theory the geometrical structure of PF5 is _________ ?

M

b. In a sketch it would look like this.

c. The F ─ P ─ F bond angles are ______________

d. PF5 is (polar; nonpolar). (Circle one)

Answer:

a. trigonal bipyramidal

b.

P

F

F

F

F

F

c. 90

o, 120

o, and 180

o

d. nonpolar

10.57 a. How does the geometrical structure of PF5 differ from that of IF5?

M

b. IF5 is (polar; nonpolar). (Circle one)

Answer: a. PF5 is trigonal bipyramidal, whereas IF5 is square pyramidal b. polar

10.58 Ozone (O3) is an allotropic form of oxygen. Use VSEPR theory to predict the geometry

M of the ozone molecule.

Answer: bent

10.59 Which should have the longer bond, B2 or B2 ─

?

H

Answer: B2 ─

10.60 Which should have the longer bond, O2 or O2+?

M

Answer: O2


10.61 Using the VSEPR Theory match the shapes of the molecules with the formula.

M

_____ 1. BeCl2 a. Linear

_____ 2. H2O b. Trigonal planar

_____ 3. SiCl4 c. Bent

_____ 4. BCl3 d. Tetrahedral

_____ 5. NH3 e. Octahedral

f. Pyramidal

Answer:

__a___ 1. BeCl2

__c___ 2. H2O

__d___ 3. SiCl4

__b___ 4. BCl3

__f___ 5. NH3

10.62 Complete the following table.

H

Hybrid type Geometry of electron pairs

a ___________ linear

b sp2 _________

c ___________ trigonal bipyramidal

d ___________ octahedral

Answer:

Hybrid type Geometry of electron pairs

a sp linear

b sp2 trigonal planar

c dsp3

trigonal bipyramidal

d sp3d

2 octahedral

10.63 The two ─ CH2 groups in C2H4 do not rotate freely around the bond connecting

M them, although the two ─ CH3 groups in C2H6 have almost unhindered rotation around the C ─ C bond. Why?

Answer: The C2H4 has pi bonding between the carbon atoms. Pi bonding restricts rotation.

10.64 In benzene, what is the hybridization on each carbon atom?

E

Answer: sp2

10.65 Predict the geometry around the central atom in each of the following molecules:

M a PO43 ─

b SO4 2 ─

c XeO4

Answer: All are tetrahedral


10.66 Which of the following molecules should be polar?

M

a CH3OH b H2O c CH3OCH3

Answer: a and b and c (mildly polar)

10.67 Which of the following molecules are bent?

M

a. H2S b. CO2 c. ClNO d. NH2─

e. O3

Answer: a, c, d, and e

10.68 Which of the following molecules are planar?

H

a. SO3 b. SO3

2 ─ c. NO3

─ d. PF3 e. BH3

Answer: a, c, and e


TRUE-FALSE QUESTIONS

10.69 According to the VSEPR theory all of the electron pair-electron pair repulsions

M about the central atom in PCl3 are of equal strength.

Answer: F

10.70 The BrF5 molecule has polar bonds and has a dipole moment.

M

Answer: T

10.71 Pi bonds are covalent bonds in which the electron density is concentrated above

E and below the inter-nuclear axis, but not cylindrically around the axis.

Answer: T

10.72 The hybridization of B in the BF3 molecule is sp3.

M

Answer: F

10.73 A bonding molecular orbital is of lower energy (more stable) than the atomic

M orbitals from which it was formed.

Answer: T

10.74 The σ2s MO is lower in energy than the σ2px MO.

E

Answer: T

10.75 Based on the MO diagram for N2 (σ2s2σ*2s

2π2py2π2pz

2σ2px2), N2 should be paramagnetic.

E

Answer: F

10.76 Molecular Orbital theory provides an explanation for the observation that O2 is a diamagnetic molecule.

E

Answer: F

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