Question

The gas we use in the kitchen is called liquified petroleum gas (LPG). In the cylinder, it exist 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.

• A. Process – A is a chemical change
• B. Process – B is a chemical change.
• C. Both processes A and B are chemical changes.
• D. None of these processes is a chemical change

Answer 1

The correct option is B

Process – B is a chemical change.

Explanation for correct option

(B)Process – B is a chemical change.

Physical change

• The changes which can be observed and specified like changes in color, hardness, rigidity, fluidity, density, melting point, boiling point, etc. are the physical changes.

Chemical change

• A chemical change is a change that results in the formation of new chemical substances.
• It involves the making or breaking of bonds between atoms.
• This change is an irreversible change.

Process A

• Process A is a physical change.
• It involves a change in the state of matter from liquid to gas.
• The gaseous LPG may be converted back to a liquid state.
• It is a reversible process.

Process B

• Process B is a chemical change.
• In the Combustion of LPG, new products are formed that as water vapor, Carbon Dioxide and heat, and very small amounts of Carbon Monoxide.

Explanation for incorrect option

• Process – B is a chemical change. Hence, options (A), (C), (D) are correct.

Hence, option (B) is correct. Process – B is a chemical change.