A solution of sodium sulphate in water is electrolysed using inert electrodes. The products at the cathode and anode are respectively:

1. H₂, O₂

2. O₂, H₂

3. O₂, Na

4. O₂, SO₂

If the E°_cell for a given reaction has a negative value, which of the following gives correct relationships for the values of $∆$G° and K_eq ?

(1) $∆$G° >0;  K_eq< 1

(2) $∆$G° >0; K_eq>1

(3) $∆$G° < 0; K_eq> 1

(4) $∆$G° <0; K_eq< 1

A device that converts energy of the combustion of fuels like hydrogen and methane, directly

into electrical energy is known as:

1. Fuel cell

2. Electrolytic cell

3. Dynamo

4. Ni-Cd cell

A button cell used in watches functions as following

Zn(s) + Ag₂O(s) + H₂O (l) $\rightleftharpoons$2Ag(s) + Zn²⁺(aq) + 2OH^-(aq)

If half cell potentials are

$$\begin{gathered} {{\mathrm{Zn}}^{2+}}_{\left(\mathrm{aq}\right)} +\hspace{0.17em}2{\mathrm{e}}^{-} \to {\mathrm{Zn}}_{\left(\mathrm{x}\right)}; {\mathrm{E}}^{\mathrm{o}} = -0.76\mathrm{V} \\ {\mathrm{Ag}}_2{\mathrm{O}}_{\left(\mathrm{s}\right)} + {\mathrm{H}}_2{\mathrm{O}}_{\left(\mathrm{l}\right)} + 2{\mathrm{e}}^{-} \to 2{\mathrm{Ag}}_{\left(\mathrm{s}\right)} + 2{{\mathrm{OH}}^{-}}_{\left(\mathrm{aq}\right)}; \\ {\mathrm{E}}^{\mathrm{o}} = 0.34\mathrm{V} \end{gathered}$$

The cell potential will be

1. 0.84 V

2. 1.34 V

3. 1.10 V

4. 0.42 V

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.