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Why does the oxidation of zinc not continue indefinitely when a Zn rod is dipped in $ZnSO_4$ solution?
ABecause all zinc atoms immediately disappear from the rod
BBecause a layer of excess positive charge forms around the rod and opposes further oxidation
CBecause sulfate ions permanently coat the rod and stop electron movement
DBecause the rod becomes positively charged and attracts electrons back from solution
Answer & Solution
Correct answer: B. Because a layer of excess positive charge forms around the rod and opposes further oxidation
As more $Zn^{2+}$ ions are produced, excess positive charge accumulates near the rod as a layer. This opposes further escape of zinc ions into solution, so oxidation is hindered. The notes describe this limiting situation as the saturation point.
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