If mercury is used as a cathode during the electrolysis of an aqueous NaCl solution, the ions discha — Electrochemistry Chemistry Question
Question
If mercury is used as a cathode during the electrolysis of an aqueous NaCl solution, the ions discharged at cathode are
Answer: B
💡 Solution & Explanation
Normally, in an aqueous solution, $H^+$ is reduced before $Na^+$. However, hydrogen gas has a very high overvoltage on a mercury cathode, making its reduction kinetically unfavorable. Consequently, $Na^+$ ions are preferentially discharged to form sodium amalgam (Na-Hg). Therefore, correct answer is B.
💬Ask on WhatsApp →
Still have doubts about this question?
Send it to our AI chemistry tutor on WhatsApp — gets answered in minutes