Question

a) What is the colour of ferrous sulphate crystals? How does this colour change after heating?
b) Name the product formed on strongly heating ferrous sulphate crystals. What type of chemical reaction occurs in this change?

Answer 1

Hint:Ferrous sulphate also known as Iron(ll) sulphate was called copperas, green vitriol in the ancient times. Iron(II) sulphate is denoted by the molecular or chemical formula $FeS{O_4}.x{H_2}O$.
Ferrous sulphate crystals are the molecules of water of crystallization which are usually heptahydrate that is seven molecules, but the value of x can be different too and can be evaporated on heating.

Complete answer:
Iron is a metal with symbol Fe. Atomic number of iron is twenty-six. It is an element of group eight and the first transition series. It is an element which is found in earth's crust. It is the fourth most common element that is found in earth's crust. It has two valencies that are plus two \[\left( { + 2} \right)\] and plus three \[\left( { + 3} \right)\].
a) Ferrous sulphate when heated it loses all the water of crystallization, that is, it loses seven water of crystallization if heptahydrate. Originally ferrous sulphate is green in colour but when it is heated, its colour changes from green to white and it loses its water of crystallization.
b) When we strongly heat ferrous sulphate crystals it goes through a decomposition reaction to give ferric oxide, sulphur dioxide and sulphur trioxide as products. When this decomposition reaction takes place, the gas released smells like burning sulphur as sulphur dioxide, sulphur trioxide is released.

Note:
The water molecules which are stuck inside the crystal structure of a salt are known as the water of crystallization or water of hydration. The salts consisting of water of crystallization in their crystal structure are known as hydrates.