Question

While performing an experiment a student observes that when he heats some green crystals in a boiling tube, the colour of the crystals changes to brown and a gas evolves which smells like burning sulphur. Interpret the observations and results.

Answer 1

Observation: The green colour of ferrous sulphate crystals changes to brownish ***** ferric oxide and smell of burning sulphur is observed.

Result: Heating of ferrous sulphate is a thermal decomposition reaction because of ferrous sulphate breaks down into simpler compounds-Fe2O3, SO2 and SO3.

2FeSO4() +Heat → Fe2O3() + SO2(g) + SO3(g)