Question

Which of the following definition(s) related to fire and explosion is/are CORRECT?

• A. Fire point is the lowest temperature at which the vapour above a liquid will continue to burn once ignited.
• B. Deflagration is the explosion in which the reaction front moves at a speed greater than the speed of sound in the unreacted medium.
• C. Detonation is the explosion in which the reaction front moves at a speed less than the speed of sound in the unreacted medium.
• D. Flash point of a liquid is the lowest temperature at which it gives enough vapour to form an ignitable mixture with air.

Hint:

Understanding fire-related terminology, such as deflagration and detonation, is important in industrial safety. Deflagration is subsonic, while detonation is supersonic. Flash point and fire point both deal with the ignition of a liquid.

Answer 1

The Correct Option is A, D

- Fire point: The fire point is the lowest temperature at which the vapour above a liquid will continue to burn once ignited. This is the correct definition for fire point.
- Deflagration: Deflagration refers to an explosion where the reaction front moves at a speed less than the speed of sound in the unreacted medium, not greater. So, option (B) is incorrect.
- Detonation: Detonation refers to the explosion where the reaction front moves at a speed greater than the speed of sound in the unreacted medium. This is the opposite of deflagration. Thus, option (C) is incorrect.
- Flash point: The flash point of a liquid is the lowest temperature at which it gives enough vapour to form an ignitable mixture with air. This is the correct definition for flash point, making option (D) correct.
Thus, the correct answers are (A) and (D).