Question

Which of the following is not true about combustion?

• A. In case of chimney, when air does not enter from below, the candle burns freely.
• B. In case of chimney, candle burns freely when air enters from below the chimney.
• C. In case of chimney, when air does not enter from below, the flame flickers and produces smoke.
• D. In the absence of air candles flame flickers but does not goes off.

Answer 1

Answer: (A)

In case of chimney, when air does not enter from below, the candle burns freely.

The statement $A$ is not true about combustion.
In case of chimney, when air enters from below, the candle burns freely. If there is no supply of air from below, the candle cannot burn freely. This is because air supply is essential for combustion.