Statuse and paintings coated with white lead turn black on long exposure to atmosphere. The original colour can be restored by treating them with H_(2)O_(2). The reason behind this is

Statuse and paintings coated with white lead turn black on long exposu

1.	Statuse and paintings coated with white lead turn black on long exposure to atmosphere. The original colour can be restored by treating them with H_(2)O_(2). The reason behind this is
Answer» blackened statues get coated with PBS which on reaction with `H_(2)O_(2)` is oxidised to WHITE `PbSO_(4)` `H_(2)O_(2)` DISSOLVES the COATING white lead and exposes the inner surface. White lead reacts with `H_(2)O_(2)` to form white `PbSO_(4)` blackened STATUSE get coated with lead sulphate which reacts with `H_(2)O_(2)` to give PbS. Solution :The statues and paintings coated with white lead get blackened due to action of `H_(2)S` present in traces in atmosphere. When these are treated with `H_(2)O_(2)`, PbS is oxidised to `PbSO_(4)` which is colourless or white. `underset("black")(PbS)+4H_(2)O_(2)to underset("white")(PbSO_(4))+4H_(2)O`