Q13 / 110 · VITEEE 2023 · Chemistry
\(\mathrm{Zn}\) amalgam is prepared by electrolysis of aqueous \(\mathrm{ZnCl}_2\) using \(\mathrm{Hg}\) cathode ( \(9 \mathrm{gm}\) ). How much current is to be passed through \(\mathrm{ZnCl}_2\) solution for 1000 seconds to prepare a \(\mathrm{Zn}\) Amalgam with \(25 \% \mathrm{Zn}\) by wt. \((\mathrm{Zn}=65.4\) )
- A\(5.6 \mathrm{amp}\)
- B\(7.2 \mathrm{amp}\)
- Correct answerC\(8.85 \mathrm{amp}\)
- D\(11.2 \mathrm{amp}\)
Solution
Let \(\mathrm{x}\) gm of \(\mathrm{Zn}\) deposit on \(9 \mathrm{gm}\) of \(\mathrm{Hg}\)
\(\begin{aligned}
& \% \text { of } \mathrm{Zn} \text { in Amalgam }=\frac{\mathrm{x}}{9+\mathrm{x}} \times 100=25 \\
& \therefore \mathrm{x}=3 \mathrm{gm}
\end{aligned}\)
Eq. of \(\mathrm{Zn}=\frac{3 \times 2}{65.4}\)
Current \(=\frac{6}{65.4} \times \frac{96500}{1000}=8.85 \mathrm{amp}\).
Hence, the correct answer is option: 'C'.