1. Soda lime is a mixture of sodium hydroxide (NaOH) and calcium oxide (CaO). It is used in granular form within recirculating breathing environments like general anesthesia and its breathing circuit, submarines, rebreathers, and hyperbaric chambers and underwater habitats. Its purpose is to eliminate carbon dioxide (CO2) from breathing gases, preventing carbon dioxide retention and, eventually, carbon dioxide poisoning. The creation of soda lime involves treating slaked lime with a concentrated sodium hydroxide solution. == Chemical components == The primary components of soda lime include: calcium oxide (CaO) constituting approximately 75%, water (H2O) accounting for around 20%, sodium hydroxide (NaOH) making up about 3%, and potassium hydroxide (KOH) present at approximately 0.1%. == Anaesthesia == During general anaesthesia, a patient's exhaled gases, containing carbon dioxide, pass through an anaesthesia machine's breathing circuit, containing a soda lime canister filled with soda lime... from wikipedia.org