Question

what reaction takes place at the anode when cucl₂ goes through electrolysis?
half-reaction | e° (v)
cl₂ + 2e⁻ → 2cl⁻ | +1.36
cu²⁺ + 2e⁻ → cu | +0.34
oxidation occurs at the anode. reduction occurs at the cathode.
options:
cu²⁺ + 2e⁻ → cu
2cl⁻ → cl₂ + 2e⁻
2cl₂ → cl⁻ + 2e⁻
cl₂ → 2cl⁻ + 2e⁻

Explanation:

1. Recall that oxidation (loss of electrons) occurs at the anode.
2. Analyze the half - reactions: The given reduction half - reactions are $\ce{Cl_{2} + 2e^{-}->2Cl^{-}}$ (reduction, gain of electrons) and $\ce{Cu^{2+}+2e^{-}->Cu}$ (reduction, gain of electrons).
3. For oxidation, we need the reverse of a reduction half - reaction. The reverse of $\ce{Cl_{2} + 2e^{-}->2Cl^{-}}$ is $\ce{2Cl^{-}->Cl_{2}+2e^{-}}$, which is an oxidation reaction (loss of electrons). The reaction $\ce{Cu^{2+}+2e^{-}->Cu}$ is a reduction reaction (not for anode). The other options $\ce{2Cl_{2}->Cl^{-}+2e^{-}}$ and $\ce{Cl_{2}->2Cl^{-}+2e^{-}}$ are not correct as they do not represent the correct reverse of the given reduction half - reaction for chloride ions.

Answer:

B. $2\ce{Cl^{-}}
ightarrow\ce{Cl_{2}} + 2\ce{e^{-}}$