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.
(d) 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?
(a) Salt XSO4 is Copper Sulphate.
(b) Colour of salt is “Blue”.
(c) Copper sulphidde is the black precipitate
(d) The chemical equation:
CuSO4 (aq.) + H2S (g) 
CuS (s) + H2SO4 (aq.)
(e) Double displacement reaction takes place.
65