What mass of $\mathrm{Mg}$ is produced during electrolysis of molten $\mathrm{MgCl}_2$ by passing $2…

What mass of $\mathrm{Mg}$ is produced during electrolysis of molten $\mathrm{MgCl}_2$ by passing $2 \mathrm{amp}$ current for 482.5 second? $\left(\right.$ Molar mass $\mathrm{Mg}=24 \mathrm{~g} \mathrm{~mol}^{-1}$ )
  1. $0.12 \mathrm{~g}$
  2. $0.24 \mathrm{~g}$
  3. $1.2 \mathrm{~g}$
  4. $0.4 \mathrm{~g}$

Solution

$\begin{aligned} & \mathrm{Mg}_{(\mathrm{s})}^{2+}+2 \mathrm{e}^{-} \longrightarrow \mathrm{Mg}_{(\mathrm{s})} \\ & \text { Mole ratio }=\frac{1 \mathrm{~mol}}{2 \mathrm{~mole}^{-}} \\ & \mathrm{W}=\frac{\mathrm{I}(\mathrm{A}) \times \mathrm{t}(\mathrm{s})}{96500\left(\mathrm{C} / \mathrm{mol} \mathrm{e}^{-}\right)} \times \text {mole ratio } \times \text { molar mass } \\ & \mathrm{W}=\frac{2 \times 482.5}{96500\left(\mathrm{C} / \mathrm{mol} \mathrm{e}^{-}\right)} \times \frac{1 \mathrm{~mol}}{2 \mathrm{~mol} \mathrm{e}^{-}} \times 24 \mathrm{~g} \mathrm{~mol}^{-1} \\ & \mathrm{~W}=0.12 \mathrm{~g}\end{aligned}$

Asked in: MHT CET 2023 (10 May Shift 1)

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