Concept:The Leclanché cell uses a chemical depolarizer to remove hydrogen gas formed during the reaction.
Explanation:During discharge, hydrogen bubbles collect on the carbon cathode and cause polarization.
This reduces the cell's efficiency by increasing internal resistance.
To prevent this, a depolarizing agent is mixed with the electrolyte.
In a Leclanché cell, manganese (IV) oxide,
MnO2, acts as the depolarizer.
It oxidizes hydrogen to water, restoring the cell's operation.
Neither powdered carbon, carbon rod, nor ammonium serves this specific purpose.
Answer:B. manganese (IV) oxide.