Question

A black mineral A on heating in air gives a gas B. The mineral A on reaction with H2SO4 gives a gas C and a compound D. Bubbling C into an aqueous solution of B gives white turbidity. The aqueous solution of compound D, on exposure to air, with NH4SCN gives a red compound E. The compounds A and E respectively, are:

Answer 1

Hey Marshal,

◆ Answer -

Mineral A => FeS

Compound E => Fe(SCN)3

● Explaination -

Supposed black mineral is FeS.

FeS (mineral A) on heating in air gives off Fe2O3 & SO2 (gas B).

FeS + O2 --> Fe2O3 + SO2

FeS (mineral A) on reaction with H2SO4 gives H2S (gas C) & FeSO4 (compound D).

FeS + H2SO4 --> FeSO4 + H2S

FeSO4 (compound D) on reaction with NH4SCN in presence of air produces Fe(SCN)3 (compound E).

FeSO4 + NH4SCN + O2 --> Fe(SCN)3 + (NH4)2SO4

Hope this is helpful for you.