Compound A is the light crystaline solid .IT gives the following tests:
i. IT dissolves in dilute sulphuric acid, NO gas is produced
ii. A drop of `MnO_(4)` is added to the above solution .The pink colour disappears
iii. Compound A is heated strongly .Gases B and C , with pungent smell , come out A brown D is left behind
iv . THe gas mixture (B and C) is passed into a dchromate solution .The solution turn green
v. THe green solution from step (iv) gives a white precipitate E with a soluttion of barium nitrate .
vi. Residue D from step (iii) is heated on charcoal in a reducing flame it gives a magnetic subsytance .Name the compounds A,B,C, D and E

Explanation

A: `FeSo_(4):B : SO_(2) ,C: SO_(4),D: Fe_(2)O_(3),E : 7H_(2)O`
It is again a problem involving `FeSO_(4),7H)_(2)O`