Elements, Compounds and Mixtures — Science STD 7 — Question

1. Distillation: It is the process of separating the components or substances from a compound. It is a process of heating a solution containing soluble solids to form vapours of the liquid and then cooling the vapours to get the liquid back.
Distillation method is used in the following:

• to separate components of air into oxygen, nitrogen, argon, etc.
• to separate salt from saltwater.
• to purify impure liquids.
• to prepare distilled water.

2. Separating funnel: When a mixture of two immiscible liquids is left undisturbed, two layers are clearly seen to have formed, (a) The heavier of the liquids remain below and the lighter liquid floats on it. (b) So two liquids in a mixture can be separated by making use of this property, e.g.

• to separate kerosene and water.
• to separate oil and water.