Question

Given the equation: 2Cr(s) + 3Pb2+(aq) ⇌ 2Cr3+(aq) + 3Pb(s), which is the correct reduction half reaction?

Answer 1

Answer:

When there is decrease in oxidation number by gain of electrons then it is known as reduction.

For example, the given reaction is as follows.

2Cr(s) + 3Pb^{2+}(aq) \rightarrow 2Cr^{3+}(aq) + 3Pb(s)

Reduction half reaction: Pb^{2+}(aq) + 2e^{-} \rightarrow Pb(s)

Oxidation half reaction: Cr(s) \rightarrow Cr^{3+}(aq) + 3e^{-}

Thus, we can conclude that option (d) is the correct reduction half reaction.