100 gms of soda lime absorbs …………………………………. % of CO2 –

**Core Concept**
Soda lime is a commonly used absorbent in anesthesia machines to remove CO2 from exhaled breaths. It is a mixture of calcium hydroxide and sodium hydroxide that reacts with CO2 to form sodium carbonate and water.

**Why the Correct Answer is Right**
Soda lime contains calcium hydroxide (Ca(OH)2) and sodium hydroxide (NaOH), which react with CO2 to form sodium carbonate (Na2CO3) and water (H2O). The reaction is as follows: Ca(OH)2 + CO2 → CaCO3 + H2O. This reaction is highly efficient and can absorb up to 80% of CO2 by weight.

**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because it does not specify a percentage, and the correct percentage is 80%.
**Option B:** This option is incorrect because it is too low; soda lime can absorb more than 60% of CO2.
**Option C:** This option is incorrect because it is too high; soda lime cannot absorb more than 80% of CO2.

**Clinical Pearl / High-Yield Fact**
It is essential to replace soda lime regularly to maintain its effectiveness and prevent rebreathing of CO2, which can lead to respiratory acidosis.

**Correct Answer: B. 60%**