Difficulty: Easy
Correct Answer: True
Explanation:
Introduction / Context:
This item checks scientific understanding of how pressure affects boiling point. Though the statements cite the standard reference points (100°C boiling and 0°C freezing at 1 atm), the conclusion asks a general physical truth.
Concept / Approach:
According to phase-equilibrium principles, lowering external pressure lowers the boiling temperature of a liquid.
Step-by-Step Solution:
At sea level (≈1 atm), pure water boils at ≈100°C.At reduced pressure (e.g., high altitudes or in a vacuum), the temperature at which vapor pressure equals external pressure is lower; hence water boils at a lower temperature.
Why Other Options Are Wrong:
“false” contradicts established thermodynamics; “either probably …” introduces unwarranted uncertainty; “Irrelevant” ignores the direct linkage between pressure and boiling point.
Final Answer:
True
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