For the galvanic cell
Zn | Zn²⁺ (1.0 M) || Cd²⁺ (1.0 M) | Cd

Which of the following represents the correct cell reaction?
1. \( \mathrm{Cd} \rightarrow \mathrm{Cd}^{2+}+2 e\)

2. \( \mathrm{Zn}^{2+} \rightarrow \mathrm{Zn}-2 e^{-} \)
3. \( \mathrm{Cd}+\mathrm{Zn}^{2+} \rightarrow \mathrm{Cd}^{2+}+\mathrm{Zn} \)
4. \(\mathrm{Zn}+\mathrm{Cd}^{2+} \rightarrow \mathrm{Cd}+\mathrm{Zn}^{2+}\)
$$

Specific conductance has the unit:
1. \(\mathrm{ohm}^{-1} \mathrm{~cm}^{-1}\)
2.\(\text { ohm.cm }\)
3.\(\text { ohm } \mathrm{cm}^{-1}\)
4. \(\mathrm{ohm}^{-1} . \mathrm{cm}\)

What is the value of ${\mathrm{pK}}_{\mathrm{b}}<mspace\; width="1em"></mspace>({\mathrm{CH}}_3{\mathrm{COO}}^{-}<mspace\; width="1em"></mspace>)$ if ${\mathrm{\lambda }}_{\mathrm{m}}^0=<mspace\; width="1em"></mspace>390<mspace\; width="1em"></mspace>\&<mspace\; width="1em"></mspace>{\mathrm{\lambda }}_{\mathrm{m}}<mspace\; width="1em"></mspace>=<mspace\; width="1em"></mspace>7.8$ for 0.04 of a $<mspace\; width="1em"></mspace>{\mathrm{CH}}_3\mathrm{COOH}$  at $25°\mathrm{C}$ ?

(A) 9.3                                               

(B) 9.2

(C) 4.7                                               

(D) 4.8

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.

How much current is necessary to produce $H_2$ gas at the rate of 1 $c{m}^3$ per second under STP ?

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