Electrochemistry MCQs Mock Test of Class 12th Chemistry

Welcome to your Electrochemistry MCQs Mock Test of Class 12th Chemistry

Question 1: Standard electrode potential for Sn4+| Sn2+ couple is + 0.15 V and that for the Cr3+| Cr couple is -0.74 . These two couples in their standard state are connected to make a cell. The cell potential will be

(a) + 0.89 V

(b)+0.18 V

(c)+1.83 V

(d)+1.199 V

Question 2: If the E°cell for a given reaction has a negative value then which of the following gives the correct relationships for the values of AG° and Keq?

(a)AG°1

(b) AG°< 0; Keq <1

(d) AG° >0; Keq <1

Question 3: Standard electrode potential of three metals X, Y and Z are -1.2 V, +0.5 V and -3.0 V respectively. The reducing power of these metals will be

(a)Y>X>Z

(b)Z>X>Y

(c)X>Y>Z

(d)Y >Z >X

Question 4: What is the time (in s) required for depositing all the silver present in 125 ml_ of 1 M AgN03 solution by passing a current of 241.25 A? (1F = 96500 C)

(a) 10

(b) 50

(d) 100

Question 5: Which of the following is widely used in the manufacture of lead storage battery?

(a) Arsenic

(b) Lithium

(d) Antimony

Question 6: An increase in equivalent conductance of a strong electrolyte with dilution is mainly due to

(a) increase in ionic mobility of ions

(b) 100% ionisation of electrolyte at normal dilution

(d) increase in number of ions

Question 7: Which of the following statements about Electrochemistry of electrolytes is not correct?

(a) Conductivity of solution depends upon size of ions

(b) Conductivity depends upon viscosity of solution

(d) Conductivity of solution increases with temperature

Question 8: Which of the following electrolytic Electrochemistry has the least specific conductance?

(a) 0.02 N

(b) 0.2 N

(d) 0.002 N

Question 9: What amount of Cl2 gas is liberated at anode, if 1A current is passed for 30 min in NaCI solution?

(a) 0.66 mole

(b)0.33 mole

(d) 0.33 g

10.

Question 10: 9.65 C of electric current is passed through fused anhydrous MgCI2. The magnesium . metal thus obtained is completely converted into a Grignard reagent. The number of moles of Grignard reagent obtained is

(a) 5 x 10-4

(b) 1×10-4

(d) 1 x 1-5

11.

Question 11: What is the current efficiency of an electrode deposition of Cu metal from CuS04 solution in which 9.80 g copper is deposited by the passage of 5A current for 2 h?

(a) 41.4%

(b) 50%

(d) 82.8%

12.

Question 12: A current of 12 A is passed through an electrolytic cell containing aqueous NiS04 solution. Both Ni and H2 gas are formed at the cathode. The current efficiency is 60%. What is the mass of nickel deposited on the cathode per hour?

(a) 7.883 g

(b) 3.941 g

(d) 2.645 g

13.

Question 13: Time required to deposit one millimole of aluminium metal by the . passage ^^65 A through molten electrolyte containing aluminium ion is

(a) 30 s

(b) 10 s

(d) 10000 s

14.

Question 14: A solution of Ni(N03)2 is electrolysed between platinum electrodes using a current of 5 A for 20 min. What mass of Ni is deposited at the cathode? (Atomic mass of Ni = 58.7)

(a) 5.87 g

(b)1.82g

(d)2.22g

15.

Question 15: In electrolysis of dil. HgSO^ what is liberated at anode?

(a) H2

(b) SO2

(d) 02

16.

Question 16: What is the cell reaction occurring in Daniell cell (Galvanic cell)?

(a) Cu(s) + ZnS04(aqf) > CuS04(aq) + Zn(s)

(b) Zn(s) + CuS04 (aq) >Cu(s) + ZnS04 (aq)

(d) 2Na(s) + CdS04 (aq) >Na2S04 (aq) + Cd(s)

17.

Question 17: Arrange the following metals in the order in which they ‘ displace each other from the solution of their salts. Al, Cu, Fe, Mg and Zn.

(a) Mg > Zn > Al > Fe > Cu

(b) Mg > Fe > Al > Zn > Cu

(d) Mg > Al > Fe > Zn > Cu

18.

Question 18: The reduction potential of hydrogen half-cell will negative if

(a) p(H2) = 1 atm and [H+] = 2.0 M

(b) p(H2) = 1 atm and [H+] = 1.0 M

(d) p(H2) = 2 atm and [H+] = 2.0 M

19.

Question 19: E1, E2 and E3 are the emfs of the following three galvanic cells respectively (i) Zn(s)|Zn2+(0.1 M)||Cu2+(1 M)|Cu(s) (ilj Zn(s)|Zn2+(1 M)||Cu2+(1M)|Cu(s) (ii) Zn(s)|Zn2+(1 M)||Cu2+(0.1 M)|Cu(s) Which one of the following is true?

(a) E2 >E1 >E3

(b) E1>E2>E3

(d) E3 >E2 >E1

20.

Question 20: The solution of CuS04 in which copper rod is immersed is diluted to 10 times, the reduction electrode potential

(a) increases by 0.030 V

(b) decreases by 0.030 V

(d) decreases by 0.059 V

21.

Question 21: The standard emf of a galvanic cell involving cell reaction with n = 2 is found to be 0.295 V at 25°C. The equilibrium constant of the reaction would be

(a)2.0x 1011

(b) 4.0 x 1012

(d) 1.0 x101°

22.

Question 22: While charging the lead storage battery,

(a) PbS04 anode is reduced to Pb

(b) PbS04 cathode is reduced to Pb

(d) PbS04 anode is oxidised to Pb02

23.

Question 23: When lead storage battery is charged

(a) lead dioxide dissolves

(b) sulphuric acid is regenerated

(d) the amount of sulphuric acid decreases

24.

Question 24: In a H2-02 fuel cell, combustion of hydrogen occurs to

(a) remove absorbed oxygen from electrode surface

(b) create potential difference between the two electrodes

(d) generate heat s

25.

Question 24: Direction (Q. Nos. 38-39) In the following questions, more than one of the answers given may be correct. Select the correct answers and mark it according to the codes. Codes

(a) 1, 2 and 3 are correct

(b) 1 and 2 are correct

(d) 1 and 3 are correct

26.

Question 25: Direction (Q. Nos. 42-44) Each of these questions contains two statements : Assertion and Reason. Each of these questions also has four alternative choices, only one of which is the correct answer. You have to select one of the codes (a), (b), (c) and (d) given below.

(a) Assertion is true, Reason is true; Reason is a correct explanation for Assertion

(b) Assertion is true, Reason is true; Reason is not a correct explanation for Assertion

(d) Assertion is false, Reason is true

27.

Q26. Which of the following is given to a fuel cell’s cathode?

a) Hydrogen

b) Nitrogen

c) Oxygen

d) Chlorine

28.

Question27: A device that converts energy of combustion of fuels like hydrogen and methane, directly into electrical energy is known as

(a) fuel cell

(b) electrolytic cell

(d) Ni-Cd cell

29.

Question 28: The quantity of electricity required to oxidise 0.1 moleof MnO42- completely to Mn0–4, is

(a) 96500 C

(b) 2x96500C

(d) 196.50 C

30.

Question29: The weight of silver (at. wt. = 108) displaced by a quantity of electricity which displaces 5600 mL of 02 at STP will be

(a) 5.4 g

(b)10.8g

(d) 108.0g

31.

Question 30: A hydrogen gas electrode is made by dipping platinum wire in a solution of HCI of pH =10 and by hydrogen gas around the platinum wire at one atm. Pressure the oxidation potential of electrode would be

(a) 0.59 V

(b) 0.118 V

(d) 0.059 V

32.

Q.31 The charge required for the reduction of 1 mol of MnO4– to MnO2 is

(a) 1 F

(b) 3 F

(d) 6 F

33.

Q.32 If limiting molar conductivity of Ca2+ and Cl– are 119.0 and 76.3 S cm2 mol-1, then the value of limiting molar conductivity of CaCl2 will be

(a) 195.3 S cm2 mol-1

(b) 271.6 S cm2 mol-1

(d) 314.3 S cm2 mol-1

34.

Q.33 NH4NC>3 is used in salt bridge because

(a) it forms a jelly like material with agar-agar.

(b) it is a weak electrolyte.

(d) the transport number of NH4+ and NO3– ions are almost equal.

35.

Q.34 The reaction, 3ClO– (aq) → ClO3 (aq) + 2Cl– (aq) is an example of

(a) Oxidation reaction

(b) Reduction reaction

(d) Decomposition reaction

36.

Q.35 The emf of the cell: Ni / Ni2+ (1.0 M) // Au3+ (1.0 M) / Au (E° = -0.25 V for Ni2+/Ni; E° = 1.5 V for Au3+/Au) is

(a) 1.25 V

(b) -1.25 V

(d) 2.0 V

37.

Q.36 The standard emf of a galvanic cell involving cell reaction with n = 2 is formed to be 0.295 V at 25° C. The equilibrium constant of the reaction would be

(a) 1.0 × 1010

(b) 2.0 × 1011

(d) 1.0 × 102

38.

Q.37 If E°Fe2+/Fe = -0.441 V and E°Fe2+/Fe2+ = 0.771 V, the standard EMF of the reaction, Fe + 2Fe3+ → 3Fe2+ will be

(a) 1.212 V

(b) 0.111 V

(d) 1.653 V

39.

Q.38 Fused NaCl on electrolysis gives ………….. on cathode.

(a) Chlroine

(b) Sodium

(d) Hydrogen

40.

Q.39 The standard electrode potentials for the half cell reactions are: Zn → Zn2-– 2e– E° = 0.76 V Fe → Fe2- + 2– E° = -0.41 V The emf of the cell reaction Fe2- + Zn → Zn2- + Fe is

(a) -0.35 V

(b) +0.35 V

(d) +1.17 V

41.

Q.40 Which of the following is a secondary cell?

(a) Leclanche cell

(b) Lead storage battery

(d) All of these

42.

Q.41 For a certain redox reaction, E° is positive. This means that

(a) ΔG° is positive, K is greater than 1

(b) ΔG° is positive, K is less than 1

(d) ΔG° is negative, K is less than 1

43.

Q.42 Cell reaction is spontaneous, when

(a) E0red is negative

(b) ΔG° is negative

(d) ΔG° is positive

44.

Q.43 Equilibrium constant K is related to E0cell and not Ecell because

(a) E0cell is easier to measure than Ecell

(b) Ecell becomes zero at equilibrium point but E0cell remains constant under all conditions

(d) any of the terms Ecell or E0cell can be used

45.

Q.44 Molar conductivity of 0.15 M solution of KCl at 298 K, if its conductivity of 0.0152 S cm-1 w ill be

(a) 124 Ω-1 cm² mol-1

(b) 204 Ω-1 cm² mol-1

(d) 300 Ω-1 cm² mol-1

46.

Q.45 Electrical conductance through metals is called metallic or electronic conductance and is due to the movement of electrons. The electronic conductance depends on

(a) the nature and structure of the metal

(b) the number of valence electrons per atom

(d) all of these

47.

Q.46 The specific conductivity of N/10 KCl solution at 20°C is 0.0212 ohm-1 cm-1 and the resistance of the cell containing this solution at 20°C is 55 ohm. The cell constant is

(a) 3.324 cm-1

(b) 1.166 cm-1

(d) 3.682 cm-1

48.

Q.47 Faraday’s law of electrolysis is related to

(a) Atomic number of cation

(b) Speed of cation

(d) Equivalent weight of electrolyte

49.

Q.48 The molar conductivity is maximum for the solution of concentration

(a) 0.004 M

(b) 0.002 M

(d) 0.001 M

50.

Q.49 Units of the properties measured are given below. Which of the properties has been not matched correctly?

(a) Molar conductance = Sm2 mol-1

(b) Cell constant = m-1

(d) Equivalence conductance = S m² (g eq)-1

51.

Q.50 How long would it take to deposit 50 g of Al from an electrolytic cell containing Al2O3 using a current of 105 ampere?

(a) 1.54 h

(b) 1.42 h

(d) 2.15 h

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