Q.47. What mass of \mathrm{Mg} is produced during the electrolysis of molten \mathrm{MgCl}_2 by passing 2 amp current for 482.5 seconds?
(Molar mass \mathrm{Mg} = 24 \, \mathrm{g} \, \mathrm{mol}^{-1})
A. 0.12 g
B. 0.24 g
C. 1.2 g
D. 0.4 g
Answer: A. 0.12 g
Explanation :-
\mathrm{Mg}^{2+}_{(\mathrm{s})} + 2 \, \mathrm{e}^- \longrightarrow \mathrm{Mg}_{(\mathrm{s})}The mass produced can be calculated using the formula:
\mathrm{W} = \frac{\mathrm{I} \, (\mathrm{A}) \times \mathrm{t} \, (\mathrm{s})}{96500 \, \mathrm{C}/\mathrm{mol}^-} \times \text{Mole ratio} \times \text{Molar mass}Substitute values:
\mathrm{W} = \frac{2 \times 482.5}{96500} \times \frac{1}{2} \times 24 = 0.12 \, \mathrm{g}