Concept:During the electrolysis of aqueous salts, multiple ions compete. At the cathode, the cation with the higher standard reduction potential wins the competition and is discharged.
Solution:- In an aqueous NaCl solution, two cations migrate to the cathode: \( Na^+ \) (from the salt) and \( H^+ \) (from the water).
- \( H^+ \) has a much higher reduction potential than \( Na^+ \).
- Consequently, \( H^+ \) is successfully reduced and discharged as \( H_2 \) gas.
- \( Na^+ \) fails to reduce and remains dissolved in the solution as a spectator ion.
Why other options are incorrect:While \( Cl^- \) and \( OH^- \) are technically not discharged at the cathode (they migrate to the anode), the question targets the specific
competing cation that fails to discharge. Therefore, \( Na^+ \) is the intended chemical answer.
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