BITSAT Chemistry Electrochemistry MCQs

Question: Stronger is oxidising agent, more is

a) Standard reduction potential of that species

b) The tendency to get it self oxidised

c) The tendency to lose electrons by that species

d) Standard oxidation potential of that species

Answer: Standard reduction potential of that species

Question: Which of the following relation represents correct relation between standard electrode potential and equilibrium constant?

Choose the correct statement(s).

a) I, II and III are correct

b) II and III are correct

c) I, II and IV are correct

d) I and IV are correct

Answer: I, II and IV are correct

Question: E° for the cell,

 at 25°C. The equilibrium constant for the cell reaction  is of the order of

a) 10^–37 

b) 10³⁷

c) 10^–17

d) 10¹⁷

Answer: 10³⁷

Question: Specific conductance of 0.1 M HA is If  the dissociation constant Ka of HA is :

a) 1.0 × 10^–5 

b) 2.25 × 10^–4

c) 2.25 × 10^–5

d) 2.25 × 10^–13

Answer: 2.25 × 10^–5

Question: The EMF of the cell Tl/Tl⁺ (0.001M) || Cu²⁺ (0.01M) /Cu is 0.83. The cell EMF can be increased by

a) Increasing the concentration of Tl⁺ ions.

b) Increasing the concentration of Cu²⁺ ions.

c) Increasing the concentration of Tl ⁺ and Cu²⁺ ions.

d) None of these

Answer: Increasing the concentration of Cu²⁺ ions.

Question: Electrolysis is carried out in three cells

(A) 1.0 M CuSO₄ Pt electrode

(B) 1.0 M CuSO₄ copper electrodes

(C) 1.0 M KCl Pt electrodes

If volume of electrolytic solution is maintained constant in each of the cell, which is correct set of pH changes in (A), (B) and (C) cell respectively ?

a) Decrease in all the three

b) Increase in all the three

c) Decrease, constant, increase

d) Increase, constant, increase

Answer: Decrease, constant, increase

Question: The equilibrium constant for the disproportionation reaction  at 25°C (E^oCu⁺ /Cu = 0.52V, E^oCu²⁺ /Cu = 0.16V) is

a) 6×10⁴  

b) 6×10⁶

c) 1.2×10⁶

d) 1.2×10^-6

Answer: 1.2×10⁶

Question: The efficiency of fuel cell is given by the expression, η is

a)

b)

c)

d) None of the above

Answer:

Question: The mass of the substance deposited when one Faraday of charge is passed through its solution is equal to

a) Relative equivalent weight

b) Gram equivalent weight

c) Specific equivalent weight

d) None of the above

Answer: Gram equivalent weight

Question: In the cell reaction   E⁰_cell = 0.46 V. By doubling the concentration of Cu²⁺, E₀^cell is

a) Doubled

b) Halved

c) Increases but less than double

d) Decreases by a small fraction

Answer: Decreases by a small fraction

Question:  is unstable in solution and undergoes simultaneous oxidation and reduction according to the reaction :

choose correct Eº for above reaction if Eº _Cu2+/Cu = 0.34 V and Eº _Cu2+/Cu+ = 0.15 V

a) –0.38 V

b) +0.49 V

c) +0.38 V

d) –0.19 V

Answer: +0.38 V

Question: A current of 2.0 A passed for 5 hours through a molten metal salt deposits 22.2 g of metal (At wt. = 177). The oxidation state of the metal in the metal salt is

a) +1

b) +2

c) +3

d) +4

Answer: +3

Question: The electrolytic cells, one containing acidified ferrous chloride and another acidified ferric chloride are connected in series. The ratio of iron deposited at cathodes in the two cells when electricity is passed through the cells will be

a) 3 : 1

b) 2 : 1

c) 1 : 1

d) 3 : 2

Answer: 3 : 2

Question: 1.08 g of pure silver was converted into silver nitrate and its solution was taken in a beaker. It was electrolysed using platinum cathode and silver anode. 0.01 Faraday of electricity was passed using 0.15 volt above the decomposition potential of silver. The silver content of the beaker after the above shall be

a) 0 g

b) 0.108 g

c) 0.108 g

d) 1.08 g

Answer: 0 g

Question: Consider the following Eº values  Under standard conditions the potential for the reaction. 

a) 0.91 V

b) 1.40 V

c) 1.68 V

d) 0.63 V

Answer: 0.91 V

Question: The number of coulombs required for the deposition of 108 g of silver is

a) 96500

b) 48250

c) 193000

d) 10000

Answer: 96500

Question: Which of the following will form the cathode with respect to iron anode in an electrolyte cell?

a) Mg

b) Al

c) Cu

d) Zn

Answer: Mg

Question:  The conductivity of a saturated solution of BaSO₄ is 3.06 × 10^–6 ohm^–1 cm^–1 and its equivalent conductance is 1.53 ohm^–1 cm² equiv^–1. The K_sp for BaSO₄ will be

a) 4 × 10^–12 

b) 2.5 × 10^–9 

c) 2.5 × 10^–13

d) 4 × 10^–6

Answer: 4 × 10^–12 

Question: In a cell that utilises the reaction  addition of H₂SO₄ to cathode compartment, will

a) Increase the E and shift equilibrium to the right

b) Lower the E and shift equilibrium to the right

c) Lower the E and shift equlibrium to the left

d) Increase the E and shift equilibrium to the left

Answer: Increase the E and shift equilibrium to the right

Question: How long a current of 3 amperes has to be passed through a solution of AgNO₃ to coat a metal surface of 80 cm² and 0.005 mm thick layer. Density of Ag is 10.5 g cm^–3.

a) 125.1 seconds

b) 12.5 seconds

c) 155.2 seconds

d) 200 seconds

Answer: 125.1 seconds