Question

Write the name of the cell which is generally used in hearing aids. Write the reactions taking place at the anode and cathode of this cell.

Answer 1

A mercury battery, used for hearing aids and electric watches, delivers a constant voltage of 1.35 V for long periods.

The half-reactions are

Anode:

Zn (Hg) + 2 OH ^̶ → ZnO (s) + H₂O + 2e ^̶

Cathode:

HgO + H₂O + 2e ^̶ → Hg (l) + 2 OH ^̶