Question

Assertion :$N{a}^{+}$ ions are discharged in preference to $H^{+}$ ions at Hg cathode. Reason: The nature of the cathode can affect the order of discharge of ions.

Read the above assertion and reason and choose the correct option regarding it.

• 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

There are certain factors that affect the discharge of electrons at electrodes.

Factors affecting the preferential discharge of ions in electrolysis:

1. The position of ion in electrochemical series.

2. The concentration of ion.

3. The nature of electrode.

Nature of the Electrode: This is not as important as either of the other two factors, except in certain cases.

For example in the electrolysis of molten sodium chloride using a mercury cathode, sodium ions are discharged in preference to hydrogen ions which are lower in the series.