The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder it exists as a liquid. When it comes out from the cylinder it becomes a gas (Change – A) then it burns (Change – B). The following statements pertain to these changes. Choose the correct one. 

Process – B is a chemical change.

The correct answer is option 2. Process – B is a chemical change.

Process A (liquid to gas): This is a physical change because the chemical composition of the LPG remains the same. It's just changing its state due to the pressure difference between inside and outside the cylinder.

Process B (burning): This is a chemical change because LPG reacts with oxygen in the air, forming new substances like carbon dioxide and water vapor. This reaction breaks the chemical bonds in the LPG molecules and forms new bonds in the products, creating entirely different substances with different properties.

Therefore, only process B, the burning of LPG, is a chemical change.