MCQs of Electrochemistry

Electrochemistry MCQs

MCQs of Electrochemistry

Showing 81 to 90 out of 158 Questions

81.

Which is the reaction at anode in electrolysis of AgNO₃ between Pt electrodes.

(a)	2NO₃^- → 2NO₂ + O₂ + 2e^-
(b)	${NO}_{3}^{-} \to {NO}_{2} + \frac{1}{2} O_{2} + e^{-}$
(c)	2H₂O → O₂ +4H⁺ + 4e^-
(d)	Pt → Pt⁺³ + 3e^-

82.

Which Nernst equation is correct for the reaction occurring in the given cell ? Mg_(s) Ι Mg²⁺_(aq) ΙΙ Cl^-_(aq) Ι Cl_{2(g, 1 atm)}

(a)	$E_{cell} = E °_{cell} - \frac{0.059}{n} \log \frac{[{Cl}^{-}]^{2}}{[{Mg}^{2 +}]}$
(b)	$E_{cell} = E °_{cell} - \frac{0.059}{n} \log \frac{[{Mg}^{2 +}]}{[{Cl}^{-}]^{2}}$
(c)	$E_{cell} = E °_{cell} - \frac{0.059}{n} \log [{Mg}^{2 +}] [{Cl}^{-}]^{2}$
(d)	$E_{cell} = E °_{cell} - \frac{0.059}{n} \log \frac{[{Mg}^{2 +}]}{[{Cl}^{-}]}$

83.

For complete deposition of Ag during electrolysis of 250 ml 0.04 M AgNO₃ 1.8 ampere current should be passed for how much time ? (Atomic mass of AgNO₃ = 108 gram mol^-1)

(a)	536.11 sec
(b)	365.11 sec
(c)	635.11 sec
(d)	563.11 sec

84.

5 ampere electric current was passed through an electrolytic cell of AgNO₃ for 2.7 hours so that; spoon can be silver plated. Each spoon requires 0.02 gram for silver layer fixing. How many spoons can be electroplated ? (Atomic mass of Ag = 108 gram mole^-1)

(a)	2720
(b)	3230
(c)	1720
(d)	2620

85.

4.5 g of aluminium (at. mass 27 amu) is deposited at cathode from Al³⁺ solution by a certain quantity of electric charge. The volume of hydrogen produced at STP from H⁺ ions in solution by the same quantity of electric charge will be

(a)	44.8 L
(b)	22.4 L
(c)	11.2 L
(d)	5.6 L

86.

What kind of change in the cell given below decreases the value of free energy change(ΔG) ?

Fe_(s) | Fe²⁺_(M1) || HCl_(M2) | H_{2(1 bar)} | Pt

(a)	By increasing the volume of the acid solution by diluting it in RHS container.
(b)	By increasing partial pressure of H₂ in RHS container.
(c)	By increasing the concentration of H⁺ in RHS container.
(d)	By increasing the concentration of Fe²⁺ in LHS container.

87.

Which of the following does not depend on stoichiometry of reaction ?

(a)	ΔG°
(b)	W_elec
(c)	K_c
(d)	E_cell

88.

When Daniell cell is opening, _____ .

(a)	volume of Zn-rod increases and the colour of CuSO₄ solution becomes deep blue
(b)	concentration of Zn²⁺ increases and that of Cu²⁺ decreases
(c)	decrease in the weight of Zn-anode = Increase in the weight of Cu-cathode
(d)	the solution of NH₄NO₃ is to be filled again in the salt bridge after a long time

89.

Oxidation potentials of X, Y and Z metals are respectively 2.36 V, -0.34 V and -0.80 V. Which of the following reactions can occur spontaneously ?

(a)	Y + 2H⁺ → Y²⁺ + H₂ and Y + ZCl → YCl + Z
(b)	2Z + 2HNO₃ → 2Z(NO₃)₂ + H₂ and 2Y + XCl₂ → 2YCl + X
(c)	2Z + H₂SO₄ → Z₂SO₄ + H₂ and X + 2ZCl → XCl₂ + 2Z
(d)	X + 2HCl → XCl₂ + H₂ and Y + 2ZNO₃ → Y(NO₃)₂ + 2Z

90.

What is the correct order of reducing agent based on the following reactions ?

(i) Metal L does not react with a salt of metal M.

(ii) Metal M dissolves in the salt solution of metal N.

(iii) Metal N does not dissolve in the salt solution of metal L.

(a)	N > M > L
(b)	L > M > N
(c)	M > L > N
(d)	M > N > L

Showing 81 to 90 out of 158 Questions