Concept:Electrolysis of a dilute acid (such as dilute \( H_2SO_4 \)) is essentially the electrolysis of water, facilitated by the acid's ions which increase electrical conductivity.
Solution:- At the cathode (reduction site): The abundant \( H^+ \) ions from the acid are easily reduced to form Hydrogen gas.
\( 2H^+ + 2e^- \rightarrow H_2 \).
- At the anode (oxidation site): Water molecules (or \( OH^- \) ions) are oxidized because the counter anions (like \( SO_4^{-2} \)) are highly stable and very difficult to oxidize compared to water.
\( 2H_2O \rightarrow O_2 + 4H^+ + 4e^- \).
- Therefore, \( H_2 \) evolves at the cathode, and \( O_2 \) evolves at the anode.
Why other options are incorrect:Chlorine gas would only evolve if you electrolyzed concentrated hydrochloric acid or brine, not a generic dilute acid. Hydrogen always evolves at the cathode (since it is a positive ion), never the anode.
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