How many Coulombs of electricity are required for the oxidation of one mol of water to dioxygen?

The amount of substance liberated on electrodes during electrolysis when $1 \ C$ of electricity is passed,is

$A$ solution of aluminium chloride is electrolysed for $30$ minutes using a current of $2 \ A$. The amount of the aluminium deposited at the cathode is $.................$
[Given : molar mass of aluminium and chlorine are $27 \ g \ mol^{-1}$ and $35.5 \ g \ mol^{-1}$ respectively,Faraday constant $= 96500 \ C \ mol^{-1}$]. (in $g$)

The approximate time duration in hours to electroplate $30 \ g$ of calcium from molten calcium chloride using a current of $5 \ A$ is [At. mass of $Ca=40$]

Aqueous copper sulphate solution and aqueous silver nitrate solution are electrolysed by $1 \ A$ current for $10 \ minutes$ in separate electrolytic cells. Will the mass of copper and silver deposited on the cathode be same or different? Explain your answer.

Calculate the time required in seconds to deposit $6.35 \ g$ of copper from its salt solution by passing a $5 \ A$ current. [Molar mass of $Cu = 63.5 \ g \ mol^{-1}$]