Electrolysis of 600 mL aqueous solution of NaCl for 5 min changes the pH of the solution to 12 .
The current in Amperes used for the given electrolysis is ___________ . (Nearest integer).
Answer (integer)
2
Solution
<p>Electrolysis of NaCl is</p>
<p>$$\mathrm{NaCl}+\mathrm{H}_2 \mathrm{O}(\mathrm{aq}) \rightarrow \mathrm{NaOH}(\mathrm{aq})+\frac{1}{2} \mathrm{Cl}_2(\mathrm{~g})+\frac{1}{2} \mathrm{H}_2(\mathrm{~g})$$</p>
<p>Since during electrolysis pH changes to 12</p>
<p>So $\left[\mathrm{OH}^{\ominus}\right]=10^{-2}$ and $\left[\mathrm{H}^{+}\right]=10^{-12}$</p>
<p>So by Faraday law</p>
<p>Gram amount of substance deposited $=$
Amount of electricity passed</p>
<p>$$\begin{aligned}
& 10^{-2} \times \frac{600}{1000} \times 96500=\mathrm{I} \times \mathrm{t} \\
& \frac{10^{-2} \times 600}{1000} \times 96500=\mathrm{I} \times 5 \times 60 \\
& \mathrm{I}=\frac{10^{-2} \times 600 \times 96500}{1000 \times 5 \times 60} \\
& \mathrm{I}=1.93 \text { ampere }
\end{aligned}$$</p>
<p>So, $\mathrm{I = 2}$ ampere (nearest integer)</p>
About this question
Subject: Chemistry · Chapter: Electrochemistry · Topic: Electrochemical Cells
This question is part of PrepWiser's free JEE Main question bank. 127 more solved questions on Electrochemistry are available — start with the harder ones if your accuracy is >70%.