Question

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

Answer 1

The mercury cell is used in the hearing aids which consists of zinc-mercury amalgam as anode and a paste of HgO and carbon at the cathode.

Anode:
$Zn\left(Hg\right)+2O{H}^{-}\to ZnO\left(g\right)+H_{2}O+2e^{-}$

Cathode:
$HgO+H_{2}O+2e^{-}\to Hg\left(l\right)+2O{H}^{-}$