A red-brown metal X forms a salt XSO4. When hydrogen sulphide gas is passed through an aqueous solution of XSO4, then a black precipitate of XS is formed along with sulphuric acid solution.
(a) What could the salt XSO4 be?
(b) What is the colour of salt XSO4?
(c) Name the black precipitate XS.
(a) By using the formula of the salt obtained in (a) above, write an equation of the reaction which takes place when hydrogen sulphide gas is passed through its aqueous solution.
(e) What type of chemical reaction takes place in this case?

Question

A red-brown metal X forms a salt XSO4. When hydrogen sulphide gas is passed through an aqueous solution of XSO4, then a black precipitate of XS is formed along with sulphuric acid solution.
(a)	What could the salt XSO4 be?
(b)	What is the colour of salt XSO4?
(c)	Name the black precipitate XS.
(a)	By using the formula of the salt obtained in (a) above, write an equation of the reaction which takes place when hydrogen sulphide gas is passed through its aqueous solution.
(e) What type of chemical reaction takes place in this case?

Accepted Answer

Copper sulphate will be the salt formed named as XSO4
Blue colour is the colour of the salt as it is copper sulphate
Copper sulphide is responsible for the black precipitate XS
CuSO4 (aq) + H2S (g) &rarr; CuS (s) + H2SO4 (aq)
Double displacement reaction in which reactant ions exchange places to form new products which results in precipitation reaction.

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