Question

Statement 1: Combustion or burning takes place only in the presence of oxygen.

Statement 2: Oxygen is a supporter of combustion.

• A. Statements (1) and (2) are true.
• B. Statement (1) is true and statement (2) is false.
• C. Statements (1) and (2) are false.
• D. Statement (1) is false, and statement (2) is true.

Answer 1

The correct option is D

Statement (1) is false, and statement (2) is true.

The key components of a combustion process are

1. A combustible substance, i.e., the fuel.
2. A supporter of the combustion process
3. The temperature at which the combustion takes place is called ignition temperature.

The explanation for statement A:

1. Heat energy is derived by burning fuels, and this process of burning is called combustion.
2. Usually, the combustion of fuels takes place in the presence of oxygen in the atmosphere.
3. Combustion can also take place in the absence of oxygen.
4. For example, magnesium can undergo combustion in the presence of chlorine gas.

The explanation for statement B:

1. In general, oxygen acts as a supporter of combustion.
2. For example, cooking gas burns in the presence of oxygen gas.
3. They will not burn in its absence.

Thus, statement (1) is false, and statement (2) is true.

Hence option (D) is correct.