How much electricity in terms of Faraday is required to produce $40.0 \text{ g}$ of $\text{Al}$ from molten $\text{Al}_2\text{O}_3$ (in $\text{ F}$)?

$Al_2O_3$ is reduced by electrolysis at low potentials and high currents. If $4.0 \times 10^4$ amperes of current is passed through molten $Al_2O_3$ for $6$ hours,what mass of aluminium is produced? (Assume $100\%$ current efficiency,at. mass of $Al = 27 \ g \ mol^{-1}$).

Two electrolytic cells containing $CuSO_4$ and $AgNO_3$ respectively are connected in series and a current is passed through them until $1 \, mg$ of copper is deposited in the first cell. The amount of silver deposited in the second cell during this time is approximately ......... $mg$ [Atomic weights of copper and silver are respectively $63.57$ and $107.88$]

When a current of $2 \ A$ is passed through a molten salt of a metal for $5 \ hours$,$22.2 \ g$ of the metal (atomic mass $= 177$) is deposited at the cathode. What is the oxidation state of the metal in the molten salt?

The same quantity of electricity was passed through solutions of salts of elements $X$,$Y$,and $Z$ with atomic masses $7$,$27$,and $48$ respectively. The masses of $X$,$Y$,and $Z$ deposited were $2.1 \ g$,$2.7 \ g$,and $7.2 \ g$ respectively. The valencies of $X$,$Y$,and $Z$ respectively are:

Three voltameters containing aqueous solutions of $H_2SO_4$,$CuSO_4$,and $AgNO_3$ are connected in series as shown. $A$ current was passed for $10 \ hours$. $10.8 \ g$ of $Ag$ was deposited at the cathode in the $(III)$ electrolytic cell during electrolysis. If the current efficiency is $50\%$,what is the magnitude of the current in amperes?