· 3 the oxidation number of chromium in k2cr2o7 is (a) 14 (b) 12 (c) 6 (d) none of these ......

1 Electrolysis is the process in which a chemical reaction takes place at the expense of

(a) chemical energy (b) electrical energy (c) heat energy (d) none of these

2 Standard hydrogen electrode has an arbitrarily fixed potential

(a) 0.00 volt (b) 1.00 volt

(c) 0.10 volt (d) none of these

3 The oxidation number of chromium in K2Cr2O7 is

(a) 14 (b) 12 (c) 6 (d) none of these

4 In the reaction 2 Fe + Cl2 ( 2FeCl3

(a) Fe is reduced (b) Fe is oxidized (c) Cl2 is oxidized (d) none of these

5. When fused PbBr2 is electrolyzed

(a) bromine appears at cathode (b) lead is deposited at the cathode

(c) lead appears at the anode (d) none of these happens

6 When aqueous solution of NaCl is electrolysed

(a) Cl2 is evolved at the cathode (b) H2 is evolved at cathode

(c) Na is deposited at the cathode (d) Na appears at the anode

7 During electrolysis of KNO3, H2 is evolved at

(a) anode (b) cathode (c) both (a) and (b) (d) none of these 8 During electrolysis of CuSO4 (aq) using Cu electrodes Cu is deposited at (a) anode (b) cathode (c) both (a) and (b) (d) none of these9 During electrolysis of fused NaCl, which of the following reaction occurs at anode (a) Cl– ions oxidized (b) Cl– ions reduced (c) Na+ ions oxidized (d) Na+ ions reduced 10 An electrochemical cell is based upon (a) acid–base reaction (b) redox reaction (c) nuclear reaction (d) none of the above

(a) electrolysis of water (b) electrolysis of molten NaCl

(c) electrolysis of aqueous HCl (d) electrolysis of aqueous NaCl

13 In a galvanic cell, the reaction occurs

2H2O ( O2 (g) + 4H+ + 4e– It occurs at the

(a) cathode (b) anode (c) cathode and anode (d) none of the above

14 Which statement below is not true for the reaction Fe3+ + e– ( Fe2+

(a) Fe3+ is reduced (b) oxidation state of Fe has changed (c) Fe3+ can act as an oxidizing agent (d) both Fe2+ and Fe3+ are called anions

11 Which one of the following will be good conductor of electricity

(a) pure distilled water (b) molten NaCl

(c) dilute solution of glucose (d) chloroform

12 Which one of the following represents the same net reaction as the electrolysis of aqueous H2SO4

AIIMS,CBSE,AIPMT, AFMC,Bio.Tech & PMT, Contact :- 9438559863, Mail at :- [email protected],www.ibiokaare.com,compiled by AKB

ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

15 During a redox reaction, an oxidizing agent

(a) gains electrons (b) is oxidized (c) loses electrons (d) is hydrolysed

16 In a salt bridge KCl is used because

(a) it is an electrolyte

(b) K+ and Cl– transfer easily

(c) agar–agar forms a good jelly with it

(d) KCl is also present in the calomel electrode

17 A oxidizing agent is a substance which brings about

(a) electron donation (b) oxidation (c) reduction (d) hydrolysis

18 In the electrolysis the process of oxidation occurs at

(a) anode (b) cathode (c) both cathode and anode (d) in electrolytic solution

19 In an oxidation process the oxidation number of the element

(a) increases (b) decreases (c) does not change (d) everything change

20 In the reduction process the oxidation number of the element

(a) increases (b) decreases (c) does not change

21 Oxidation number of oxygen in OF2 is

(a) + 1 (b) – 1 (c) + 2 (d) – 2

22 The e.m.f. of Zn – Cu cell is (a) 1.10 v (b) 1.5 v (c) 2.0 v (d) 2.5 v

23 The standard reduction potential of a standard hydrogen electrode (a) 0.0 v (b) 1.1 v (c) 1.5 v (d) 2.0 v

24 The oxidation number of Mn is K2 MnO4 is (a) + 2 (b) + 4 (c) + 6 (d) + 7

25 Which of the following is the definition of oxidation (a) gain of electrons (b) loss of electrons (c) addition of H2 (d) removal of O2

26 During electrolysis of H2SO4 (aq) O2 is evolved at (a) cathode (b) anode (c) both a and b (d) none of these

27 The e.m.f. produced by a voltage cell is (a) electrode potential (b) reduction potential (c) cell potential (d) oxidation potential


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

28 Which of the following is not a redox reaction

(a) CaCO3 ( CaO + CO2

(b) Cu + 4HNO3 ( Cu(NO3)2 + 2NO2 + H2O

(c) 2H2 + O2 ( 2H2O

(d) MnO2 + 4HCl ( MnCl2 + Cl2 + 2H2O

29 Which element acts as a reducing agent in the reaction Zn + H2SO4 ( ZnSO4 + H2

(a) Zn (b) H (c) S (d) O

30 Which element acts as a oxidizing agent in the reaction MnO2 + 4HCl ( MnCl2 + Cl2 + 2H2O

(a) Mn (b) O (c) H (d) Cl 31 When the current is passed through an electrolytic solution, which of the following process will occur (a) anions move towards anode and cations move towards cathode (b) cations and anions both move towards anode (c) cations and anions both move towards anode (d) no movement of the ions occur 32 Electric current passes through both molten and solution form of NaCl because of (a) ionic bonding (b) Na+ and Cl– ions (c) ions of water (d) hydration of ions 33 A cell which produces electric current by redox reaction is called (a) standard cell (b) voltaic cell (c) reversible cell (d) concentration cell 34 Which of the following conduct electricity due to the migration of electrons only (a) copper metal (b) NaCl molten (c) NaCl (d) NaCl solution 35 Oxidation number of sulphur in S2O eq \a\co1(2–,3 ) is (a) + 6 (b) – 2 (c) + 2 (d) + 4 36 Substances through which electric current can pass are called (a) insulators (b) conductors (c) cathode (d) anode 37 Substances through which electric current cannot pass are called (a) insulators (b) conductors (c) anode (d) cathode 38 Metallic conduction is due to the (a) movement of electrons (b) movement of ions (c) both (a) and (b) (d) none of these

39 Metallic conductors conduct electricity (a) with chemical change (b) without any chemical change (c) both (a) and (b) (d) none of these 40 The flow of electrons is called (a) electrolyte (b) electric current (c) cathode (d) anode

41 A substance which in molten state or in solution form allows electric current to pass through it is called (a) electrolyte (b) insulator (c) conduction (d) none of these


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

42 The process in which electric current is used to carry out a non–spontaneous redox

reaction is called

(a) electrolyte (b) electrolysis (c) metallic conductor (d) electrodes

43 In electrochemical cells, the electrode at which the reduction occurs is called

(a) anode (b) cathode (c) electrolyte (d) electrolysis

44 The process of producing a chemical change in an electrolytic cell is called

(a) electrolyte (b) electrolysis (c) electrodes (d) conductor

45 The process in which ionic compound when fused or dissolved in water split up into charged particles is called

(a) electrolysis (b) hydration (c) ionization (d) conduction

46 An apparatus in which chemical energy in converted to electrical energy is called

(a) electrolytic cell (b) galvanic cell (c) fuel cell (d) down cell

47 The metallic conductors in contact with the solution are called

(a) insulator (b) electrodes (c) electrolyte (d) down cell

48 The reaction in a galvanic cell is

(a) spontaneous (b) non–spontaneous (c) acid–base (d) none of these

49 Caustic soda is obtained by electrolysis of conc. aqueous solution of NaCl in a cell

called

(a) Daniell’s cell (b) Nelson’s cell (c) Down’s cell (d) Voltaic cell

50 Sodium metal is obtained by the electrolysis of fused NaCl in a cell is called

(a) Nelson’s cell (b) Down’s cell (c) Daniell cell (d) Voltaic cell

51 The e.m.f. of Daniell cell can be increased by

(a) increasing the area of electrode

(b) increasing the concentration of oxidising ion in the solution

(c) increasing the concentration of reducing ion in the solution

(d) adding the dil H2SO4

52 Metal and their ionic salts both conduct electricity. Which of the following statement is

not correct both

(a) are good conductors normally (b) are ionic in nature (c) decompose on passing current (d) are normally solid

53 The branch of chemistry which deals with the relationships between electricity and chemical reaction is called (a) chemical kinetics (b) electrochemistry (c) stiochiometry (d) thermochemistry


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

54 A system containing of electrodes that dips into an electrolyte in which a chemical

reaction either uses or generates an electric current is called

(a) voltaic cell (b) electrochemical cell (c) voltaic or galvanic cell (d) fuel cell

55 A cell in which spontaneous redox reaction generates an electric current is called

(a) electrolytic cell (b) electrochemical cell (c) voltaic orgalvanic cell (d) biological cell 56

A cell in which an electric current drives a non–spontaneous reaction is called

(a) electrolytic cell (b) voltaic cell (c) biological cell (d) electrochemical cell

57 A process for converting one metal with a thin layer of another metal is called

(a) electrolysis (b) electroplating (c) electrode potential (d) standard electrode

58 In an electrical connection between cathode and anode of a voltaic cell,

electrons flow from the

(a) anode to the cathode (b) cathode to the anode (c) both (a) and (b) (d) none of these

59 Greater the value of standard reduction potential of a species indicates (a) greater its

tendency to accepted electrons (b) lesser tendency to accept electrons

(c) greater tendency to lose electrons (d) none of these

60 In lead accumulator the electrolyte H2SO4 solution is

(a) 30 % (b) 60% H2SO4 (c) 80% (d) 90%

61 In alkaline battery, the electrolyte contains

(a) MnO2 (b) KOH (c) NaCl (d) NaNO3

62 Alkali metals have

(a) lower value of reduction potential than coinage metals

(b) higher value of reduction potential than coinage metals

(c) equal values of reduction potential to coinage metals

(d) none of these

63 Strong reducing agents have

(a) greater positive value of standard reduction potential

(b) greater negative value of standard reduction potential

(c) lesser positive value of standard reduction potential

(d) none of these

64 Strong oxidizing agents have

(a) greater positive value of standard reduction potential

(b) lesser positive value of standard reduction potential

(c) greater negative value of standard reduction potential

(d) none of these


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

65 The electrode with more negative value of reduction potential acts as

(a) cathode (b) anode (c) electrode (d) none of these

66 Metals which are above SHE in electrochemical series

(a) can liberate H2 from acid (b) cannot liberate H2 from acid

(c) cannot always liberate H2 from acid (c) none of these

67.Corrosion reactions are

(a) spontaneous redox reactions (b) non–spontaneous redox reactions

(c) spontaneous acid–base reactions (d) none of these

68 Voltaic cell can be changed into

(a) electrochemical cell (b) electrolytic cell (c) reversible cell (d) primary cell

69 Strongest oxidizing agent in the electrochemical series is

(a) Li (b) F (c) H2 (d) I2

70 Strongest reducing agent in the electrochemical series is

(a) Li (b) F (c) H2 (d) I2


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

Electrochemistry Multiple Choice

2MnO4- + 3ClO3

- + H2O 3ClO4- + 2MnO2 + 2OH-

-

2Cr2O72-

(aq) + 16H+(aq) + 3C2H5OH(g) 4Cr3+

(aq) +11H2O(l) + 3CH3COOH(aq)

3ClO2- 2ClO3

- + Cl- (basic)The reduction half-reaction that occurs is

B. ClO2- + 2H2O Cl- + 4OH- + 4e-

C. ClO2- + 2OH- + 2e- ClO3

- + H2OD. ClO2

- + 2OH- ClO3- + H2O + 2e-

C. Ti2+, Cd2+, V2+ D. Ti2+, V2+, Cd2+


71. Consider the following redox reaction:

72. Consider the following reaction that occurs in abreathalyzer:

75. Consider the following redox reaction:

77. Consider the following electrochemical cell:

78. Which of the following affects the potentials ofelectrochemical cells?


The reducing agent isa. H2O b. ClO3

c. MnO2 d. MnO4

Which atom undergoes an increase in oxidationnumber?a. carbon b. oxygenc. hydrogen d. chromium

73. Which of the following is the strongest reducingagent?a. Al b. Cuc. Zn d. Mg

74. Which of the following reactions is spontaneous atstandard conditions?a. Pb + Cu2+ Cu + Pb 2+

b. H2 + Mg2+Mg + 2H+

c. Br2 + 2Cl- Cl2 + 2Br-

d. 2Ag + Cu2+ Cu + 2Ag+

- + 2H2O + 4e- Cl- + 4OH-A. ClO2

76. Vanadium metal, V, reacts spontaneously with

Cd2, but not with Ti2. Based on these results, theorder of oxidizing agents, from strongest to weakest, isA. Cd2+, V2+, Ti2+ B. V2+, Ti2+ , Cd2+

In this operating electrochemical cell,a. electrons flow toward the Cu and the Cu2ionsmigrate toward the Zn.b. electrons flow toward the Cu and the Zn2ionsmigrate toward the Cu.c. electrons flow toward the Zn and the Cu2ionsmigrate toward the Zn.d. electrons flow toward the Zn and the Zn2ionsmigrate toward the Cu.

a. I and II only. b. II and III only.c. I and III only. d. I, II and III.

79. In the rusting of iron, the reduction reaction thatoccurs isa. Fe Fe2+ + 2e-

b. Fe2+ + 2e-Fec. 2H2O O2 + 4H+ + 4e-

d. O2 + 2H2O + 4e- 4OH-

80. During a cathodic protection, the sacrificial anodea. accepts electrons from the protected metal.b. reacts spontaneously with the protected metal.c. oxidizes more readily than the protected metal.d. causes the protected metal to become an anode.

ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

- H2CO3

- C. S2O82-

B. ClO4- D. Cr2O7

2-

What changes occur when the cell is in operation?

- B. acidified SO42-

C. acidified MnO4- D. acidified Cr2O7

2-

2Cr2O72- + 16H+ + 3C2H5OH 4Cr3+ + 11H2O +


85. Consider the following:NO2 N2O3 The nitrogen atom in each NO2

87. Consider the following half-reaction:1 AsH3 + __ H2O __ H3AsO3 + ? H+ + __e-

89. Consider the following electrochemical cell:

91. Ethanol, C2H5OH, is oxidized by an acidifieddichromate solution according to the followingequation:

92. Which of the following must be present to producerust by the corrosion of iron?


81. During the electrolysis of an aqueous solution ofKI, what substance is formed at the cathode?a. iodine b. oxygenc. hydrogen d. potassium

82. When electroplating an iron medallion with nickel,a. the medallion is an anode.b. the cathode is pure nickel.c. the solution contains Ni2.d. the anode reaction is Ni22eNi

83. Which of the following represents the formation ofa stronger acid as a result of oxidation?a. H2SO3 H2S b. HClO4 HClc. H2SO3 H2SO4 D. HCO3

84. Chlorine has an oxidation number of 5 ina. NaClO b. NaClO2

c. NaClO3 d. NaClO4

a. loses one electron. b. gains one electron.c. loses two electrons. d. gains two electrons.

86. Which of the following is the strongest oxidizingagent?A. BrO3

When this half-reaction equation is balanced, thecoefficient for Hisa. 2 b. 3c. 6 d. 9

88. When a strip of zinc is placed in a 1.0M copper (II)chloride solution,a. no change occurs. b. the [Clincreases.c. the [Cu2increases. d. the [Zn2increases.

90. A redox titration is performed in order todetermine the [H2O2].Which of the following wouldnot be a suitable reagent to use?A. acidified IO3

3CH3COOHThe Efor the reaction above is 2.98V. The Efor theoxidation of ethanol isa. 0.52V b. 1.23Vc. 1.75V d. 2.98V

a. I only b. II onlyc. I and II only d. I, II and III

ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

C. H2SO3 D. S2O82-

C. Sn2+ D. MnO4-

C. H2O D. C6H12O6

C. 1.0M Sr2+ D. 1.0M Mn2+


93. Why can an object not be plated with magnesiumusing 1.0M MgI2?

98. A solution containing an unknown cation reactsspontaneously with both zinc and copper. Theunknown cation isA. 1.0M H+ B. 1.0M Ag+

isA. -10 B. -5C. +5 D. +10

97. The oxidation number of P in H4P2O7


a. Water is a stronger reducing agent than Ib. Water is a stronger oxidizing agent than Ic. Water is a stronger reducing agent than Mg2d. Water is a stronger oxidizing agent than Mg2

94. In the electrolysis of 1.0M Na2SO4, what is formedat the cathode?A. O2 B. H2

95. Which of the following is capable of acting both asan oxidizing agent and a reducing agent?A. H+ B. Na+

96. Consider the following redox reaction:C2H12O6 + 6O2 6CO2 + 6H2OThe substance undergoing reduction isA. O2 B. CO2

99. Which of the following half-reactions is balanced?a. CIO- + H2O +e- Cl2 + 2OH-

b. 2CIO- + H2O +2e- Cl2 + 3OH-

c. 2CIO- + 2H2O +2e- Cl2 + 4OH-

d. 2CIO- + 2H2OCl2 + 4OH- + 2e-

100. Which of the following is a spontaneous redoxreaction?a. Ag+ + I- AgIb. Ag+ + Fe2+ Ag + Fe3+

c. 3Ag+ + Au 3Ag + Au3+

d. 2Ag+ + Ni2+ 2Ag + Ni

ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

1 2 3 4 5 b a c b b

6 7 8 9 10 b b b a b

11 12 13 14 15 b a b d a

16 17 18 19 20 b ca a b21 22 23 24 25 c a a c b26 27 28 29 30 b c a a a

31 32 33 34 35 a b b a c

36 37 38 39 40 b a a b b

41 42 43 44 45 a b b b c

46 47 48 49 50 b b a b b

51 52 53 54 55 c b b b c

56 57 58 59 60 a b a a a

61 62 63 64 65 b a b a b

66 67 68 69 70 a a c b a

Question Answer Question Answer Question Answer Question Answer71 B 83 C 95 C 37 D72 A 84 C 96 A 37 B73 D 85 B 97 C 38 C74 A 86 C 98 B 39 C75 A 87 C 99 C 40 C76 A 88 D 100 B 41 D77 B 89 A 42 B78 D 90 B 43 B79 D 91 C 44 B80 C 92 C 45 C81 C 93 D 46 D82 C 94 B 47 D


ww

w.ibiokaare.com

ww

w.ibiokaare.com

ww

w.ibiokaare.com

· 3 the oxidation number of chromium in k2cr2o7 is (a) 14 (b) 12 (c) 6 (d) none of these ......

Documents