$A$ certain current liberated $0.504 \ g$ of hydrogen in $2 \ hours$. How many grams of copper can be liberated by the same current flowing for the same time in a copper sulphate solution?

$250 \ mL$ of a waste solution obtained from the workshop of a goldsmith contains $0.1 \ M \ AgNO_3$ and $0.1 \ M \ AuCl$. The solution was electrolyzed at $2 \ V$ by passing a current of $1 \ A$ for $15 \ minutes$. The metal/metals deposited will be
$(E^0_{Ag^+/Ag} = 0.80 \ V, E^0_{Au^+/Au} = 1.69 \ V)$

Three voltameters containing aqueous solutions of $H_{2}SO_{4}$,$CuSO_{4}$,and $AgNO_{3}$ are connected in series as shown in the figure. $A$ current was passed for $10 \ hours$. $10.8 \ g$ of $Ag$ was deposited at the cathode in the $(III)$ electrolytic cell during electrolysis,given that the current efficiency is $50 \%$. If $Z_{1}$,$Z_{2}$,and $Z_{3}$ are the electrochemical equivalents for the formation of $H_{2}$,$Cu$,and $Ag$ respectively,then the ratio $Z_{1} : Z_{2} : Z_{3}$ is:

On passing $0.5 \ F$ of electricity through $NaCl$,the amount of $Cl_2$ gas deposited at the anode is .............. $g$.

$A$ $4 \ A$ current is passed through a solution of zinc sulphate for $50 \ min$. Find the amount of zinc deposited at the cathode in $g$.

$A$ current of $0.4 \ A$ is passed through excess of molten $MgCl_2$ for $9.65 \times 10^4 \ sec$. The mass of $Mg$ deposited at the cathode is .............. $gm$