Soda Lime Exothermic Water — FRCA Primary MCQ
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Correct answer: E — Exothermic producing heat and water
The CO2 absorption reaction: CO2 + 2NaOH → Na2CO3 + H2O and CO2 + Ca(OH)2 → CaCO3 + H2O. These reactions are exothermic (producing heat which helps warm inspired gas) and produce water (helping humidify inspired gas). An increase in canister temperature can indicate appropriate CO2 absorption activity. Fresh soda lime contains approximately 15% water.
Reference: Al-Shaikh Stacey 2019 Essentials of Anaesthetic Equipment