iron 2 sulphide is heated with dil H2SO4 and the gas pass through the lead acetate solution tell the observations ​

(i) Sulphur-di-oxide gas is evolved. Colourless, gas with smell of burning sulphur. It turns acidified potassium dichromate orange to green.

(ii) Hydrogen sulphide gas is evolved. Colourless gas with smell of rotten eggs. It turns lead acetate paper black.