Introduction:
Physical changes refer to changes in the physical properties of a substance without altering its chemical composition. These changes are usually reversible and do not involve the formation of new substances. The options given in the question represent various processes, and we need to identify the one that does not involve a physical change.

Explanation:
Let's analyze each option to determine if it represents a physical change or not:

a) Boiling of water to give water vapor:
When water is heated to its boiling point, it undergoes a physical change and transforms into water vapor. This is a phase change, and the chemical composition of water remains the same. Therefore, option 'a' represents a physical change.

b) Melting of ice to give water:
When ice is heated, it melts and changes from a solid state to a liquid state. This is a physical change as the chemical composition of water remains unchanged. Hence, option 'b' represents a physical change.

c) Dissolution of salt in water:
When salt is dissolved in water, it forms a homogeneous solution. This is also a physical change as no new substances are formed, and the chemical composition of salt remains the same. Thus, option 'c' represents a physical change.

d) Combustion of Liquefied Petroleum Gas (LPG):
Combustion is a chemical change that involves the reaction of a substance with oxygen to produce new substances. In the case of LPG combustion, it reacts with oxygen to produce carbon dioxide, water vapor, and heat. This is not a physical change as the chemical composition of LPG is altered, and new substances are formed. Therefore, option 'd' represents a chemical change, not a physical change.

Conclusion:
Based on the analysis, the correct answer is option 'd' - Combustion of Liquefied Petroleum Gas (LPG). This process involves a chemical change rather than a physical change, as it results in the formation of new substances.