Question

When ferrous sulphate crystals are heated in a test tube, we observe that ______.

Options

• A colourless gas with no smell is evolved.

• A brown gas is evolved.

• The green colour of the salt fades and a gas with the smell of burning sulphur is evolved.

• The green colour of the salt fades and no gas is evolved.

Answer 1

When ferrous sulphate crystals are heated in a test tube, we observe that the green colour of the salt fades and a gas with the smell of burning sulphur is evolved.

Explanation:

When heated, green ferrous sulphate crystals lose water and decompose to form reddish-brown ferric oxide, while emitting sulphur dioxide and sulphur trioxide gases. Sulphur dioxide gas is identified by its characteristic pungent smell of burning sulphur.