Assertion: In an electrochemical cell, KCl cannot be used as a salt bridge electrolyte if the anodic or cathodic compartment contains Ag⁺ or Pb²⁺ ions.

Reason:  A salt bridge is used to maintain electrical neutrality and minimize the liquid-liquid junction potential..

1. Both (A) and (R) are true, and (R) is the correct explanation of (A).
2. Both (A) and (R) are true, but (R) is not the correct explanation of (A).
3. (A) is true, but (R) is false.
4. (A) is false, but (R) is true.

What will be the quantity of iron deposited by ferrous and ferric ion by 1F (Fe = 56) :

1.  14g, 9.3 g                                          

2.  28g, 18.6 g

3.  56g, 37.2g                                         

4.  None of the above

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.

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.