Question

Assertion :Passage of charge through CuSO${}_4$(aq) solution in presence of Pt electrode increases its pH. Reason: Concentration of [OH${}^{-}$] in solution decreases.

• 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. Assertion is incorrect but Reason is correct.

Answer 1

The correct option is A Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.

Passage of charge through $CuS{O}_4\left(aq\right)$ solution in presence of Pt electrode results in the following electrode reactions.
At anode, $2H_{2}O\to 4H^{+}+O_2+4e$
$2O{H}^{-}\to H_{2}O+\frac{1}{2}{O}_2+2e$
At cathode, $C{u}^{2+}+2e\to Cu.$.
Hence, the hydrogen ion concentration increases and the hydroxide ion concentration decreases.
Hence, the pH of the solution increases.
Thus, Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.