MCQs of Electrochemistry

Electrochemistry MCQs

MCQs of Electrochemistry

Showing 91 to 100 out of 158 Questions

91.

The equilibrium constant of the reaction :
Cu_(s) + 2Ag⁺_(aq) → Cu²⁺_(aq) + 2Ag_(s);
E° = 0.46 V at 298 K is

(a)	2.0 × 10¹⁰
(b)	4.0 × 10¹⁰
(c)	4.0 × 10¹⁵
(d)	2.4 × 10¹⁰

92.

Al₂O₃ is reduced by electrolysis at low potentials and high currents. If 4.0 × 10⁴ amperes of current is passed through molten Al₂O₃ for 6 hours, what mass of aluminium is produced ? (Assume 100% current efficiency. At. mass of Al = 27 g mol^-1)

(a)	8.1 × 10⁴ g
(b)	2.4 × 10⁵ g
(c)	1.3 × 10⁴ g
(d)	9.0 × 10³ g

93.

The equivalent conductance of \frac{M}{32} solution of a weak monobasic acid is 8.0 mho {cm}^{2} and at infinite dilution is 400 mho {cm}^{2} . The dissociation constant of this acid is :

(a)	1.25 × 10^-6
(b)	6.25 × 10^-4
(c)	1.25 × 10^-4
(d)	1.25 × 10^-5

94.

A solution contains Fe²⁺, Fe³⁺ and I^- ions. This solution was treated with iodine at 35°C. E° for Fe³⁺ / Fe²⁺ is +0.77V and E° for I₂ / 2I^- = 0.536V. The favourable redox reaction is :

(a)	I₂ will be reduced to I^-
(b)	There will be no redox reaction
(c)	I^- will be oxisied to I₂
(d)	Fe²⁺ will be oxisied to Fe³⁺

95.

A : Galvanised iron does not rust. R : Zinc has a more negative electrode potential than iron.

(a)	a
(b)	b
(c)	c
(d)	d

96.

Hydrofluoric acid is a weak acid . At 25 ° C, the molar conductivity of 0.002 MHF is 176.0 Ω^{- 1} {cm}^{2} {mole}^{- 1} . If its Λ ° m = 405.2 Ω^{- 1} {cm}^{2} {mol}^{- 1} . Equilibrium constant at the given concentration is

_____

(a)	6.7 × 10^-4M
(b)	3.2 × 10^-4M
(c)	6.4 × 10^-5M
(d)	3.2 × 10^-5M

97.

{E^{0}}_{{Al}^{3 +} | Al}

= -1.66 V and

{E^{0}}_{{Fe}^{3 +} | Fe}

= 0.04 V, which of the two will be stronger reductant ?

(a)	Al³⁺
(b)	Fe³⁺
(c)	Al
(d)	Fe

98.

The potential of the electrochemical cell based on the reaction given below is 1.1 V at 25°C.

${Zn}_{(s)} + {Cu}^{2 +}_{(aq)} ⇌ {Zn}^{2 +}_{(aq)} + {Cu}_{(s)}$

What will be potential of the cell at 25°C if the concentration of Zn²⁺ and Cu²⁺ ions each is 0.1 M?

(a)	1.10
(b)	0.10
(c)	-1.10
(d)	-0.10

99.

The values of standard reduction potentials of Zn²⁺/Zn, Ni⁺²/Ni and Fe⁺²/Fe are respectively -0.76 , -0.23 and -0.44 volt. Under which conditions will the following reaction occur spontaneously ?

X + Y²⁺ → X²⁺ + Y

(a)	X = Ni, Y = Zn
(b)	X = Fe, Y = Zn
(c)	X = Zn, Y = Ni
(d)	X = Ni, Y = Fe

100.

Which of the following is the correct expression to determine E°_cell for the reaction

a A + b B ⇌ c C + d D

(a)	$E_{cell} + R T \log \frac{{[a]}^{A} {[b]}^{B}}{{[c]}^{C} {[d]}^{D}}$
(b)	$E_{cell} + \frac{R T}{n F} \ln \frac{{[C]}^{c} {[D]}^{d}}{{[A]}^{a} {[B]}^{b}}$
(c)	$E_{cell} + \frac{R T}{n F} \log \frac{{[C]}^{C} {[D]}^{D}}{{[A]}^{A} {[B]}^{B}}$
(d)	$E_{cell} + \frac{R T}{n F} \log \frac{{[a]}^{A} {[b]}^{B}}{{[c]}^{C} {[d]}^{D}}$

Showing 91 to 100 out of 158 Questions