Concept:A liquid boils when its vapor pressure equals the external ambient pressure. Modifying the external pressure shifts the boiling temperature.
Formula:$$ P_{\text{ext}} \uparrow \implies \text{Boiling Point} \uparrow $$
Solution:- Under standard atmospheric pressure (exactly 760 torr), pure water boils at exactly \( 100^\circ\text{C} \).
- If we wish to force water to remain a liquid until it reaches a higher temperature of \( 110^\circ\text{C} \), we must suppress the vapor bubbles from forming.
- To do this, we must apply an external pressure that is significantly greater than standard atmospheric pressure (> 760 torr).
- The only option range that provides pressures greater than 760 torr is 760-1200 torr.
Why other options are incorrect:Options A, C, and D represent pressures strictly lower than standard atmospheric pressure (< 760 torr). Subjecting water to these lower pressures would cause it to boil at temperatures
below \( 100^\circ\text{C} \), not above it.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.