Faraday's laws of electrolysis will fail when

How many faraday of electricity is required to produce $10 \ g$ of calcium metal (molar mass $= 40 \ g \ mol^{-1}$) from calcium ions (in $F$)?

In the Hall process,aluminium is produced by the electrolysis of molten $Al_2O_3$. How many seconds would it take to produce enough aluminium by the Hall process to make a case of $24$ cans of aluminium soft-drink,if each can uses $5.0 \ g$ of $Al$,a current of $9650 \ A$ is employed,and the current efficiency of the cell is $90.0 \ \%$?

$A$ constant current was passed through a solution of $AuCl_4^-$ ion between gold electrodes. After a period of $10.0 \ \text{minutes}$,the increase in mass of cathode was $1.314 \ \text{g}$. The total charge passed through the solution is . . . . . . $\times 10^{-2} \ \text{F}$. (Given atomic mass of $Au = 197$)

$A$ current of $2.0 \ A$ is passed for $5 \ hours$ through a molten metal salt,which deposits $22.2 \ g$ of metal (At. wt. $= 177$). The oxidation state of the metal in the metal salt is:

The current flowing in a copper voltameter is $3.2 \ A$. The number of copper ions $(Cu^{2+})$ deposited at the cathode per minute is