Question

The two aqueous solutions, $A$ $(AgNO_{3})$ and $B \,(LiCl)$, were electrolysed using $Pt$ electrodes. The $pH$ of the resulting solutions will

• A. increase in A and decrease in B
• B. decrease in both
• C. increase in both
• D. decrease in A and increase in B

Answer 1

Answer: (D)

$AgNO_{3}$
$AgNO_{3} + H_{2}O \to Ag + H^{+} + NO_{3}^{-} + \frac{1}{2} O_{2}$
In $AgNO_{3}$ solution, $[H^{+}]$ ion increases so pH decreases.
$LiCl + H_{2}O \to Li^{+} + OH^{-} + \frac{1}{2} Cl_{2} + \frac{1}{2} H_{2}$
In $LiCl$ solution, $[OH^{-}]$ ion increases so pH increases.