In an electroplating experiment,$m \ g$ of silver is deposited when $4 \ A$ of current flows for $2 \ min$. The amount (in $g$) of silver deposited by $6 \ A$ of current flowing for $40 \ s$ will be:

Consider the following reaction:
$MnO_4^- + 8H^{+} + 5e^- \rightarrow Mn^{2+} + 4H_2O$,$E^\circ = 1.51 \ V$
The quantity of electricity required in Faraday to reduce five moles of $MnO_4^-$ is ..... .

Salts of $A$ (atomic weight $8$),$B$ (atomic weight $18$) and $C$ (atomic weight $50$) were electrolysed under identical conditions using the same quantity of electricity. It was found that $2.4 \ g$ of $A$ was deposited,the weight of $B$ and $C$ deposited are $1.8 \ g$ and $7.5 \ g$ respectively. The valences of $A$,$B$ and $C$ are,respectively,

How many moles of electrons (how many Faradays of electricity) are required to reduce $1 \ mol$ of $MnO_4^-$ to $MnO_2$?

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 $KClO_{3} = 122.6 \ g \ mol^{-1}, F = 96500 \ C \ mol^{-1}$)

Salts of $A, B$ and $C$ were electrolysed under identical conditions using the same quantity of electricity. It was found that when $2.1 \ g$ of $A$ was deposited,the weights of $B$ and $C$ deposited were $2.7 \ g$ and $9.6 \ g$. If the atomic mass of $A, B$ and $C$ are $7, 27$ and $64$ respectively,then the valencies of $A, B$ and $C$ respectively are: