In electrolysis of NaCl with Pt electrode is taken the H is liberated ...
Explanation:
Electrolysis of NaCl involves the reduction of sodium ions and the oxidation of chloride ions. The reduction of sodium ions occurs at the cathode, while the oxidation of chloride ions occurs at the anode.
When a Pt electrode is taken as a cathode, hydrogen ions (H+) are reduced to hydrogen gas (H2) at the cathode. However, when a Hg electrode is used as a cathode, sodium ions (Na+) are reduced to form sodium amalgam (NaHg), instead of hydrogen gas.
The reason for this difference is the relative reactivity of the two cathode materials. Hg is more inert than Pt, meaning that it is less likely to participate in chemical reactions. As a result, it requires more voltage to reduce H+ ions to hydrogen gas at the Hg cathode than it does at the Pt cathode.
This is due to the fact that the reduction potential of H+ ions is higher than the reduction potential of Na+ ions. Therefore, to reduce H+ ions to hydrogen gas, a higher voltage is required than to reduce Na+ ions to sodium amalgam.
In summary, the reason that Hg forms sodium amalgam instead of liberating hydrogen gas in the electrolysis of NaCl is due to the relative reactivity of the two cathode materials. Hg is more inert than Pt and requires more voltage to reduce H+ ions to hydrogen gas, making it more favorable to reduce Na+ ions to form sodium amalgam instead.