question_answer 29)

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)

Answer:

 (d) Combustion of Liquefied Petroleum Gas (LPG) is a chemical change. Because it is an irreversible reaction and new products, carbon dioxide and water vapour are formed and lot of heat is also produced during the reaction. Rest three are physical changes as no new products are formed.