When $1 \ F$ of electricity is passed through acidulated water,the volume of $O_2$ evolved at $STP$ is ............. $dm^{3}$.

When a copper voltameter is connected with a battery of $e.m.f.$ $12 \ V$,$2 \ g$ of copper is deposited in $30 \ minutes$. If the same voltameter is connected across a $6 \ V$ battery,then the mass of copper deposited in $45 \ minutes$ would be ............. $g$.

The atomic weights of silver and copper are $108$ and $64$ respectively. $A$ silver voltameter and a copper voltameter are connected in series,and when current is passed,$10.8 \ g$ of silver is deposited. The mass of copper deposited will be ............. $g$.

$CuSO_4$ solution is electrolysed for $15 \ minutes$ to deposit $0.4725 \ g$ of copper at the cathode. The current in amperes required is (Faraday $= 96,500 \ C \ mol^{-1}$,atomic weight of copper $= 63$)

What is the number of moles of electrons passed when a current of $5 \ A$ is passed through a solution of $FeCl_3$ for $20 \ minutes$?

One gram of metal ion $M^{3+}$ is discharged by the passage of $1.81 \times 10^{23}$ electrons. What is the atomic weight of the metal?