Which of the following is not a physical change?
Combustion of Liquified Petroleum Gas (LPG)
The explanation for the correct option:
Physical change: The changes in which there is only change in physical property and no new substance is formed.
Chemical change: The changes in which there is a change in chemical composition and a new substance is formed during the process. Generally, these types of reactions are irreversible reactions.
(D) Combustion means burning which means a reaction in which oxygen is involved. Here, the LPG is mostly propane () and on burning, it is producing heat energy, water (), and Carbon dioxide as the product. Hence, this process is a chemical change and not a physical change.
The explanation for incorrect options:
A: Boiling of water to give water vapor is a physical change because no new substance is formed. There is a change in the state of water from the liquid state to a gaseous state.
B: Melting of ice to form water is also a physical change as there is only a change in the state of water from solid to liquid.
C: Dissolution of salt is also a change in which the state of salt is changing from a solid-state to a liquid state by dissociation of sodium chloride into its ions. Hence, it is a physical change.
Conclusion: Hence, the Correct option is D i.e., Combustion of Liquified Petroleum Gas (LPG).