Which of the following definition(s) related to fire and explosion is/are CORRECT?
Show Hint
- Fire point is the lowest temperature at which the vapour above a liquid will continue to burn once ignited.
- Deflagration is the explosion in which the reaction front moves at a speed greater than the speed of sound in the unreacted medium.
- Detonation is the explosion in which the reaction front moves at a speed less than the speed of sound in the unreacted medium.
- Flash point of a liquid is the lowest temperature at which it gives enough vapour to form an ignitable mixture with air.
The Correct Option is A, D
Solution and Explanation
Step 1: Fire point.
- The fire point is correctly defined as the lowest temperature at which vapours above a liquid will continue to burn once ignited.
- Hence, (A) is correct.
Step 2: Deflagration vs Detonation.
- Deflagration is a subsonic combustion process: the reaction front moves at a speed less than the speed of sound.
- Detonation is supersonic combustion: the reaction front moves at a speed greater than the speed of sound.
- Therefore, statements (B) and (C) are incorrect because they are swapped.
Step 3: Flash point.
- The flash point is the lowest temperature at which a liquid gives off sufficient vapour to form an ignitable mixture with air.
- This is correctly stated in (D).
Final Answer: \[ \boxed{(A) \text{ and } (D)} \]
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