31) Three metal cations A, B and C are having standard reduction potential values as 0.73, -2.17 and -1.15 V respectively. The order of reducing power of corresponding metals is:

a) C > A > B
b) A > B > C
c) B > C > A
d) C > B > A

ANSWER : B > C > A

32) …………. cell directly converts the free energy of a chemical reaction into electricity.

a) Lead storage battery.
b) Fuel cell.
c) Leclanche cell
d) Concentration cell.

ANSWER : Concentration cell.

33) In an electrochemical cell:

a) potential energy changes into electrical energy.
b) chemical energy changes into electrical energy.
c) kinetic energy decreases.
d) potential energy decreases.

ANSWER : chemical energy changes into electrical energy.

34) If the pH of the solution is 2 then cathodic reaction involves:

a) Oxidation of H⁺
b) Reduction of X^-
c) Reduction of H⁺
d) None of these.

ANSWER : Reduction of H⁺

35) Due to the presence of …………… NaCl conducts electricity.

a) free ions
b) free atoms
c) free molecules
d) free electrons

ANSWER : free ions

36) Which one of the following is a false statement?

a) Salt bridge maintains electrical neutrality
b) When salt bridge is removed then the potential of the cell drops to zero.
c) Salt bridge increases the emf of the cell.
d) Salt bridge connects two half cells.

ANSWER : Salt bridge increases the emf of the cell.

37) The chemical equivalent of the metal is 19.3. When 3A of electric current is passed for 50 min. what will be the amount of metal deposited from an electrolyte?

a) 1.8 g
b) 0.9 g
c) 3.6 g
d) 4.2 g

ANSWER : 1.8 g

38) A current of x A flowing for 10 min deposits 3g of the metal which is monovalent. The atomic mass of the metal is 50. Find the value of x?

a) 10.5
b) 9.65
c) 8.75
d) 6.72

ANSWER : 9.65

39) NaCl in solid form does not conduct electricity because:

a) It does not ionize
b) It ionizes
c) It is present in fused form
d) None of these.

ANSWER : It does not ionize

40) When I0A current is passed for 96.5 sec for electrolysis of Al (NO₃)₃. Find the number of aluminium atoms deposited at cathode?

a) 2 x 10²³

b) 2 x 10²⁴

c) 2 x 10²²

d) 2 x 10²¹

ANSWER : 2 x 10²¹   

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