Critical Pressure Definition — FRCA Primary MCQ
Instant feedback + full explanation. One question, done properly.
Educational content. Not a substitute for clinical judgement or local policy.
Reveal the answer and explanation
Correct answer: E — The pressure required to liquefy a gas at its critical temperature
The critical pressure is the minimum pressure required to liquefy a gas at its critical temperature. For N2O: critical temperature 36.5°C / critical pressure 7180 kPa. For O2: critical temperature -118°C / critical pressure 5050 kPa. Since O2's critical temperature is far below room temperature it cannot be liquefied in cylinders and exists only as compressed gas.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment