Ferrous sulphate decomposes with the evolution of a gas having a characteristic odour of burning

2FeSO4(s) + Heat → Fe2O3(s) + SO2(g) + SO3(g) It is a thermal decomposition reaction

Potassium permanganate solution (KMnO4) is an oxidising agent. It oxidises ferrous sulphate (FeSO4) to ferric sulphate [Fe2(SO4)3].

The colour of ferrous sulphate crystals is green. On heating, FeSO4.7H2O first decomposes to form anhydrous ferrous sulphate (FeSO4) which is white in colour.

The correct answer is (B) brown

(B) (i), (iv)

(C) irritating choking smell

The correct answer is (C) vinegar

Al displaces Fe from FeSO4 and forms Al2(SO4)3 which is colourless. The lower end of the test tube becomes warm.

(i) Green to white, then brown  (ii) Water  (iii) As of burning sulphur  (iv) Ferric oxide, sulphur dioxide, sulphur trioxide (v) Decomposition reaction

Iron absorbed by plants is Ferric