The time required to remove electrolytically one fourth of $Ag^+$ from $0.2 \ L$ of $0.1 \ M \ AgCl$ solution by a current of $0.1 \ A$ is approximately $.......... \ min$.

An electric current is passed through a silver voltameter connected to a water voltameter. The cathode of the silver voltameter weighed $0.108 \ g$ more at the end of the electrolysis. The volume of oxygen evolved at $STP$ is ............... $cm^{3}$.

Potassium chlorate is prepared by electrolysis of $KCl$ in basic solution as shown by the following equation:
$6 OH^{-} + Cl^{-} \rightarrow ClO_{3}^{-} + 3 H_{2}O + 6 e^{-}$
$A$ current of $x \ A$ has to be passed for $10 \ h$ to produce $10.0 \ g$ of potassium chlorate. The value of $x$ is $.......$ (Nearest integer).
(Molar mass of $KClO_{3} = 122.6 \ g \ mol^{-1}, F = 96500 \ C \ mol^{-1}$)

Copper is a divalent metal. The value of its electrochemical equivalent is $3.29 \times 10^{-4} \ g/C$. Its atomic mass is (in $g/mol$)

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 ............. $g$.

Three faradays of electricity were passed through an aqueous solution of iron $(II)$ bromide. The weight of iron metal (atomic weight $= 56$) deposited at the cathode (in $g$) is