Calculate the equilibrium constant (K) for a reaction involving a two-electron transfer,
 if the standard emf of the cell at 25°C is 0.295 V.

$1.<mspace\; width="1em"></mspace>\mathrm{2.95\; \times \; 10⁻²}$

$2.<mspace\; width="1em"></mspace>\mathrm{1.0\; \times \; 10¹}$

3.    2.95 × 10¹⁰

4.   1.0 × 10¹⁰

Find the number of faradays required to produce one mole of water in a hydrogen-oxygen fuel cell
using aqueous alkali as the electrolyte.

Calculate the current required to produce hydrogen gas at a rate of 1 cm³ per second at STP during electrolysis.

1.   4.305 amp                                           

2.   17.22 amp

3.   8.61 amp                                            

4.   2.1525 amp.

A current of 0.250 A is passed through 400 ml of a 2.0 M solution of NaCl for 35 minutes. What will be the pH of the solution after the current is turned off ?

1.  12.98                            

2.  12.13

3.  10.48                            

4.  9.24

During discharge of a lead storage cell, the density of sulphuric acid in the cell-

1. Increases.                                     

2. Decreases.

3. Remains unchanged.                      

4. Initially increases but decreases subsequently.

Find the condition under which the cell reaction for the following electrochemical cell is spontaneous:

Pt | H₂(P₁) | H⁺(1 M) || H⁺(1 M) | H₂(P₂) | Pt

The standard electrode potentials (reduction) of Pt/Fe³⁺, Fe²⁺ and Pt/Sn⁴⁺, Sn²⁺ are + 0.77 V and + 0.15 V respectively at 25°C. The standard EMF of the reaction Sn⁴⁺ + 2Fe²⁺ → Sn²⁺ + 2Fe³⁺ is :

1.   – 0.62 V                                        

2.   – 0.92 V

3.   + 0.31 V                                        

4.   + 0.85 V

Specific conductance of 0.01 M KCl solution is x $oh{m}^{-1}c{m}^{-1}$. When conductivity cell is filled with 0.01 M KCl the conductance observed is y $oh{m}^{-1}$. When the same cell is filled with 0.01 M$<mspace\; width="1em"></mspace>H_2<mspace\; width="1em"></mspace>S{O}_4$ the observed conductance was $z<mspace\; width="1em"></mspace>oh{m}^{-1}<mspace\; width="1em"></mspace>c{m}^{-1}.$ Hence specific conductance of 0.01 M $H_2<mspace\; width="1em"></mspace>S{O}_4$ is-

(a) xz                                                                

(b) z/xy

(c) xz/y                                                             

(d) xy/z

Why can F₂ gas not be obtained by the electrolysis of any F⁻ salt?

1.  Fluorine is the strongest reducing agent

2.  Fluorine is the strongest oxidising agent.

3.  Fluorine readily reacts with atmospheric O₂

4.   All of the above

Calculate the quantity of electricity (i.e. charge) delivered by a Daniel cell initially containing 1L each of \(1 M C u^{2 +}\)ion and \(1 M Z n^{2 +} ,\)which is operated until its potential drops to 1V.
(Given : \(E_{Zn2+/Zn}^0 = -0.76V; E_{Cu2+/Cu}^0 = +0.34V\))

1. 0.029 x 10⁵ C
2. 2.239 x 10⁵ C
3. 1.92 x 10⁵ C
4. 3.123 x 10⁵ C