Question:
Which of the following is not a physical change ?
(a) Boiling of water to give water vapours
(b) Melting of ice to give water
(c) Dissolution of salt in water
(d) Combustion of Liquefied Petroleum Gas (LPG)
Solution:
(d). LPG is a mixture of gases like propane (C3Hg) and butane (C4H10) in liquefied form. These are chemical substances and undergo combustion
upon heating with air or oxygen. It is therefore, a chemical change.