The amount of copper metal deposited at the cathode on passing an electric current of $500 \, mA$ for $20 \, minutes$ in a cupric chloride solution is ............ $g$.

How much electricity is required in Faraday to produce $40.0 \ g$ of $Al$ from molten $Al_2O_3$? (Atomic mass of $Al = 27 \ g \ mol^{-1}$)

$A$ 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 .............. $gm$

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:

The unit of Faraday is

Aluminium oxide may be electrolysed at $1000 \, ^\circ C$ to furnish aluminium metal (At. Mass $= 27 \, amu$; $1 \, F = 96,500 \, C$). The cathode reaction is $Al^{3+} + 3e^- \to Al^0$. To prepare $5.12 \, kg$ of aluminium metal by this method would require: