How many faradays of electricity is required to produce $4.8 \mathrm{~g}$ of $\mathrm{Mg}$ at cathode in the…
How many faradays of electricity is required to produce $4.8 \mathrm{~g}$ of $\mathrm{Mg}$ at cathode in the electrolysis of molten $\mathrm{MgCl}_{2} ?$ (Molar mass of $\mathrm{Mg}=24 \mathrm{~g} / \mathrm{mol}$ )
$0.4 \mathrm{~F}$
$4 \mathrm{~F}$
$10 \mathrm{~F}$
$40 \mathrm{~F}$
Solution
$\mathrm{Mg}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mg}$ (at cathode)
$24 \mathrm{~g}$ of $\mathrm{Mg}=2 \mathrm{~F}$ of electricity
$\therefore 4.8 \mathrm{~g}$ of $\mathrm{Mg}=\frac{4.8 \times 2}{24}=0.4 \mathrm{~F}$ of electricity.