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Entonox Separation Temperature — FRCA Primary MCQ

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ModeratePhysics & Clinical MeasurementEntonox Separation TemperatureFRCA Primary

Entonox separates into its constituent gases at the pseudocritical temperature of approximately:

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Correct answer: C — −7°C

Entonox separates at approximately −7°C. Below this liquid N2O separates to the bottom with oxygen-rich gas above. If used in this state oxygen-rich gas is delivered first followed by a hypoxic mixture. Cylinders should be stored above 10°C and inverted before use if cooled.

Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment