The amount of charge required for the reduction of 1 mol of ${\mathrm{MnO}}_4^{-}$ to ${\mathrm{Mn}}^{2+}$ is -

$1.$ $4.8$ $\times$ ${10}^5$ $\mathrm{C}$
$2.$ $3.2$ $\times$ ${10}^6$ $\mathrm{C}$
$3.$ $1.8$ $\times$ ${10}^5$ $\mathrm{C}$
$4.$ $4.1$ $\times$ ${10}^4$ $\mathrm{C}$

The number of Faradays required to produce 20.0 g of Ca from molten CaCl₂ is-

1. 2F

2. 1F

3. 4F

4. 3F

Three electrolytic cells A, B, C containing solutions of ZnSO₄, AgNO₃, and CuSO₄, respectively are connected in series.

A steady current of 1.5 amperes was passed through them until 1.45 g of silver was deposited at the cathode of cell B. The current flow time is-

1. 14 minutes

2. 25 minutes

3. 20 minutes

4. 11 minutes

The electricity required in coulombs for the oxidation of 1 mole of FeO to ${\mathrm{Fe}}_2{\mathrm{O}}_{\mathrm{3 }}$is:

The mass of nickel deposited by electrolysis of a solution of $\mathrm{Ni}{\left({\mathrm{NO}}_3\right)}_2$ using a current of 5 amperes for 20 min is: 
(Atomic mass of Nickle is 58.7u)

1. 2.42 g

2. 1.82 g

3. 3.93 g

4. 6.42 g