Question

Assertion :At the end of electrolysis using Pt electrodes, an aqueous solution of $CuS{O}_4$ turns colorless. Reason: $CuS{O}_4$ changes to $Cu(OH{)}_2$ during elctrolysis.

• A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
• B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
• C. Assertion is correct but Reason is incorrect
• D. Both Assertion and Reason are incorrect

Answer 1

The correct option is C Assertion is correct but Reason is incorrect

(A) is correct.

Since $C{u}^{2+}$ ions are reduced to Cu and deposited at cathode. $H_{2}O$ is oxidized at anode. $S{O}_4^{2-}$ is not oxidized)
$H_{2}O\to 2H^{\oplus }+2e^{-}+\frac{1}{2}{O}_2$

$2H^{\oplus }+S{O}_4^{2-}\to H_{2}S{O}_4$.

The solution becomes colourless due to the formation of $H_{2}S{O}_4$ in solution.

(R) is an incorrect statement.