Q41 / 200 · Manipal (MET) 2014 · Chemistry
Suppose that gold is being plated on to another metal in an electrolytic cell. The half-cell reaction producing the $\mathrm{Au}(\mathrm{s})$ is $\mathrm{AuCl}_4{ }^{-} \rightarrow \mathrm{Au}(s)+4 \mathrm{Cl}^{-}-3 e^{-}$
If a 0.30 A current runs for 15.00 min , what mass of $\mathrm{Au}(s)$ will be plated, assuming all the electrons are used in the reduction of $\mathrm{AuCl}_4^{-}$? The Faraday constant is $96485 \mathrm{C} / \mathrm{mol}$ and molar mass of Au is 197 .
If a 0.30 A current runs for 15.00 min , what mass of $\mathrm{Au}(s)$ will be plated, assuming all the electrons are used in the reduction of $\mathrm{AuCl}_4^{-}$? The Faraday constant is $96485 \mathrm{C} / \mathrm{mol}$ and molar mass of Au is 197 .
- Correct answerA0.184 g Au
- B1.84 g Au
- C0.551 g Au
- D0.613 gAu
Solution
$\begin{aligned} & \text {Mass of } \mathrm{Au} \text { deposited }=\text { Number of Faraday passed } \times \text { Eq. mass } \\ & =\frac{0.30 \times 15 \times 60}{96485} \times \frac{197}{3}=0.184 \mathrm{~g}\end{aligned}$
Hence, the correct answer is option: 'A'.