High temperatures will affect the CO2 absorbent. Which statement is true?

• A. True, it will affect the CO2 absorbent
• B. False, high temperatures do not affect it
• C. Only when humidity is high
• D. Only during heavy breathing

Answer: (B)

Temperature affects how well the CO2 absorbent (soda lime) works in a closed-circuit system. The CO2 removal reaction is exothermic and relies on moisture to proceed efficiently. When the bed heats up, the reaction shifts in a way that can reduce CO2 uptake, and higher temperatures can dry the absorbent, lowering its capacity and promoting less effective absorption. Humidity helps because water participates in the chemical process, but high temperature alone can still diminish performance if the bed becomes too dry or overheated. So, the idea that high temperatures don’t affect the absorbent isn’t accurate—their influence is real and tied to both the chemical reaction and the moisture balance in the bed. Heavy breathing increases CO2 production and can stress the bed, but temperature itself directly alters absorption efficiency.