Consider the following reduction processes :
Zn²⁺ + 2e^– $$ \to $$ Zn(s) ; E^o = – 0.76 V
Ca²⁺ + 2e^– $$ \to $$ Ca(s); E^o = –2.87 V
Mg²⁺ + 2e^– $$ \to $$ Mg(s) ; E^o = – 2.36 V
Ni² + 2e^– $$ \to $$ Ni(s) ; E^o = – 0.25
The reducing power of the metals increases in the order :

If the standard electrode potential for a cell is 2 V at 300 K, the equilibrium constant (K) for the reaction

Zn(s) + Cu²⁺ (aq) $$\rightleftharpoons$$ Zn²⁺(aq) + Cu(s)

at 300 K is approximately,

(R = 8 JK^$$-$$1mol^$$-$$1, F = 96000 C mol^$$-$$1)

The anodic half-cell of lead-acid battery is recharged using electricity of 0.05 Faraday. The amount of PbSO₄ electrolyzed in g during the process is : (Molar mass of PbSO₄ = 303 g mol^$$-$$1)

When 9.65 ampere current was passed for 1.0 hour into nitrobenzene in acidic medium, the amount of p-aminophenol produced is :