Question

H₂O₂ is used to restore oil paintings. Explain giving reasons.

Answer 1

White lead in the oil paintings get blackened due to action of H₂S present in atmosphere in traces.
$$\begin{gathered} Pb(OH{)}_2.2PbC{O}_3+3H_{2}S\to 3PbS+2C{O}_2+4H_{2}O \\ WhiteleadBlack \end{gathered}$$
When blackened PbS are treated with H₂O₂, the PbS is oxidized to PbSO₄ which is white in colour. So the painting is restored again.

$$\begin{gathered} PbS+4H_2{O}_2\to PbS{O}_4+4H_{2}O \\ White \end{gathered}$$