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Q42 (CDS-I/2002) Science & Technology › Basic Science (Physics, Chemistry, Biology) › Thermal physics Answer Verified

Assertion(A): It is dangerous to pour water on hot oil while cooking. Reason (R): Boiling point of water is higher than that of cooking oil.

Result
Your answer: —  Â·  Correct: C
Explanation

Assertion (A) is true because pouring water on hot oil is extremely dangerous. When water, which is denser than oil, is added to hot oil, it sinks and instantly vaporizes into steam [t1, t5]. This rapid phase change causes a massive volume expansion (roughly 1,600 times), which forcefully ejects hot oil droplets into the air, leading to severe burns or grease fires [t5, t10]. Reason (R) is false because the boiling point of water (100°C) is significantly lower than that of most cooking oils, which typically have smoke points between 175°C and 250°C [t4, t7]. It is precisely because the oil is much hotter than the boiling point of water that the water flashes into steam explosively upon contact [t2, t9]. Therefore, while the assertion is a valid safety warning, the reason provided is scientifically incorrect.

Sources

  1. [1] https://www.sciencedirect.com/science/article/abs/pii/S1359431116311723
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