What Is the Half-Reaction That Occurs at the Cathode During

question 101

Multiple Choice

What is the half-reaction that occurs at the cathode during electrolysis of an aqueous potassium iodide solution?
Reduction Half-Reaction
E° (V)
K⁺(aq) + e^- K(s) -2.93
Mg²⁺(aq) + 2e^- Mg(s) -2.37
2H₂O(l) + 2e^- H₂(g) + 2OH^-(aq) -0.83
2H⁺(aq) + 2e^- H₂(g) 0.00
I₂(s) + 2e^- 2I^-(aq) 0.54
O₂(g) + 4H⁺(aq) + 4e^- 2H₂O(l) 1.23

• A)H₂O(l)→ 1/2 O₂(g)+ 2H⁺(aq)+ 2e^-
• B)2H₂O(l)+ 2e^- → H₂(g)+ 2OH^-(aq)
• C)K(s)→ K⁺(aq)+ e^-
• D)K⁺(aq)+ e^- → K(s)
• E)I₂(aq)+ 2e^- → 2I^-(aq)

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