**Core Concept**
Soda lime is a mixture used for removing carbon dioxide from anesthetic gases, particularly in anesthesia machines. It is a key component in maintaining proper anesthetic gas composition and preventing rebreathing of CO2. The composition of soda lime affects its efficacy and durability.

**Why the Correct Answer is Right**
The correct composition of soda lime is a mixture of calcium hydroxide (lime), sodium hydroxide (soda), and water. Calcium hydroxide reacts with CO2 to form calcium carbonate, which absorbs the CO2. The reaction occurs as follows: Ca(OH)2 + CO2 → CaCO3 + H2O. This reaction is crucial for the effective removal of CO2 from anesthetic gases.

**Why Each Wrong Option is Incorrect**
* **Option A:** This option might be incorrect because it does not specify the exact composition of soda lime. A mixture without calcium hydroxide or sodium hydroxide would not effectively absorb CO2.
* **Option B:** This option might be incorrect because it includes potassium hydroxide instead of sodium hydroxide. Although both are strong bases, the correct composition of soda lime specifically includes sodium hydroxide.

**Clinical Pearl / High-Yield Fact**
It is essential to replace soda lime regularly to prevent the buildup of heat, which can lead to an explosion. The color of soda lime changes from blue to pink as it becomes saturated with CO2, indicating the need for replacement.

**Correct Answer:** C. Calcium hydroxide, sodium hydroxide, and water.