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 :

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

(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.