WAEC Physics 2020 Paper

Concept:The depolariser removes hydrogen gas formed during the reaction to prevent polarisation.Explanation:In a Leclanche cell, hydrogen gas collects at the positive electrode during operation.This hydrogen layer reduces the efficiency of the cell.Manganese (IV) oxide, $\mathrm{MnO}_2$, oxidises this hydrogen to water.So, $\mathrm{MnO}_2$ acts as the depolarising agent.Answer:C. manganese (IV) oxide