One litre of 1 M CuSO₄ solution is electrolysed. After passing 2F charge, the molarity of CuSO₄ solution will be

• M/2

• Zero

• M/4

• M

Same amount of electric current is passed through solutions of AgNO₃ and HCl. If 1.08 g of silver is obtained in the first case, the amount of hydrogen liberated at STP in the second case is

• 224 cm³

• 1.008 gm

• 112 cm³

• 22400 cm³

The standard reduction potentials of Zn and Ag in water at 298 K are, Zn²⁺ + 2e^- $\rightleftharpoons$ Zn; E° = -0.76 V and Ag⁺ + e^- $\rightleftharpoons$ Ag; E° = +0.80 V? Which of the following reactions take place?

• Zn²⁺ (aq) + 2Ag (s) → 2Ag⁺ (aq) + Zn (s)

• Zn (s) + 2Ag⁺ (aq) → Zn²⁺ (aq) + 2Ag (s)

• Zn²⁺ (aq) + Ag⁺ (aq) → Zn (s) + Ag (s)

• Zn (s) + Ag (s) → Zn²⁺ (aq) + Ag⁺ (aq)

In a galvanic cell, the electrons flow from

• anode to cathode through the solution

• cathode to anode through the solution

• anode to cathode through the external circuit

• cathode to anode through the external circuit

Aluminium displaces hydrogen from dilute HCl whereas silver does not. The e.m.f. of a cell prepared by combining Al / Al³⁺ and Ag/Ag+ is 2.46 V. The reduction potential of silver electrode is + 0.80 V. The reduction potential of aluminium electrode is

• + 1.66 V

• -3.26 V

• 3.26 V

• -1.66 V

The hydrogen electrode is dipped in a solution of pH 3 at 25°C. The potential would be (the value of 2.303 RT/F is 0.059 V)

• 0.177 V

• 0.087 V

• 0.059 V

• - 0.177 V

187.

Corrosion of iron is essentially an electrochemical phenomenon where the cell reactions are

• Fe is oxidised to Fe²⁺ and dissolved oxygen in water is reduced to OH^-.

• Fe is oxidised to Fe³⁺ and H₂O is reduced to O${}_2^{2-}$.

• Fe is oxidised to Fe²⁺ and H₂O is reduced to O${}_2^{-}$.

• Fe is oxidised to Fe²⁺ and H₂O is reduced to O₂.

The standard electrode potential is measured by

• electrometer

• voltmeter

• pyrometer

• galvanometer

When a quantity of electricity is passed through CuSO₄ solution, 0.16 g of copper gets deposited. If the same quantity of electricity is passed through acidulated water, then the volume of H₂ liberated at STP will be : [given : atomic weight of Cu = 64]

• 4.0 cm³

• 56 cm³

• 604 cm³

• 8.0 cm³

Which one of the following condition will increase the voltage of the cell represented by the equation?

Cu(s) + 2Ag⁺(aq) $\rightleftharpoons$Cu²⁺(aq) + 2Ag(s)

• Increase inthe dimension of Cu electrode

• Increase in the dimension of Ag electrode

• Increase inthe concentration of Cu²⁺ ion.

• Increase in the concentration of Ag⁺ ions.