Question

liquid like petrol and acctan are kept in cool places .why?

Answer 1

because their Ignition Temperatures are low and they an catch fire if stored in warm places or under direct sunlight.

Answer 2

Ether and acetone both have relatively low boiling points. This means that if they are not refrigerated they will evaporate and become a gas. Gaseus ether and acetone are not as useful and are more difficult to use.