Which of the following is not a physical change?
(a) Boiling of water to give water vapour
(b) Melting of ice to give water
(c) Dissolution of salt in water
(d) Combustion of Liquefied Petroleum Gas (LPG)
Combustion of Liquefied Petroleum Gas (LPG) is a chemical change because it is an irreversible chemical reaction. It involves formation of new products like carbon dioxide, water vapour alongwith a lot of heat.
In rest of the cases, only physical state is changing and no new products are formed. Hence, they are physical changes.