A black coloured compound x is formed by the action of `H_(2)S` on lead paintings.The colour of lead painting is restored by using compound Y which convert x to compound Z then

A black sulphide is formed by the action of H_(2)S on

A black sulphide is formed by the action of H_(2)S on:

The compound H_2N -Hg-O-Hg-I is formed by the action of

The compound used in the treatment of lead poisoning is :

The compound used in the treatment of lead poisoning is :

Name the compound which gives blue colour to the glass.

The compound formed by the reaction of ethyl chloride with a sodium-lead alloy at 400°C is:

H_(2)O_(2) restores the colour of old lead paintings, blackened by the action of H_(2)S gas by :

(i)A black coloured compound (B) is formed on passing H_(2)S through the solution of a compound (A) in NH_(4)OH (ii) (B) on treatment with HCl and potassium chlorate or aquaregia gives (A) (iii) (A) on treatment with KCN gives a buff/reddish-brown coloured precipitate which dissolves in excess of this reagent forming a compound ( C) . (iv)The compound ( C) is changed into a compound (D) when its aqueous solution is boiled in air. (v)The solution of (A) was treated with excess of NaHCO_(3) & then with bromine water. On cooling & shaking for some time, a green colour of compound (E) is formed.No change is observed on heating. Identify (A) to (E) and give chemical equations.

Explain, why hydrogen peroxide is used for restoring the colour of old lead paintings?