Statues coated with white lead on long exposure to atmosphere

hydrogen
cbse

#1

Statues coated with white lead on long exposure to atmosphere turn black and the original colour can be restored on treatment with $H_{ 2 }$$O_{ 2 }$. Why?


#2

On long exposure to atmosphere, white lead is converted into black PbS due to the action of $H _{ 2 }S$ present in the atmosphere. As a result, statues turn black.

On treatment of these blackened statues with $H_{ 2 }$$O_{ 2 }$, the black PbS gets oxidised to white $PbSO_{4}$ and the colour is restored.