All are constituents of soda lime except
**Core Concept**
Soda lime is a crucial component in the absorption of carbon dioxide in anesthesia systems. It is a mixture of calcium hydroxide (also known as slaked lime), sodium hydroxide, and water. The key constituents of soda lime are responsible for its ability to absorb carbon dioxide through a chemical reaction.
**Why the Correct Answer is Right**
The correct answer is not listed among the options, so we will assume one of the options is incorrect. However, to proceed, let's fill in the options: A. Calcium hydroxide, B. Sodium hydroxide, C. Potassium hydroxide, D. Calcium chloride. Among these, the constituent that does not belong in soda lime is **Option D: Calcium chloride**. This is because calcium chloride is not a typical component of soda lime, whereas the other options are essential for its function.
**Why Each Wrong Option is Incorrect**
**Option A:** Calcium hydroxide is a primary component of soda lime, responsible for its high pH and ability to absorb carbon dioxide. It reacts with carbon dioxide to form calcium carbonate, which is a key step in the absorption process.
**Option B:** Sodium hydroxide is another essential component of soda lime, contributing to its high pH and facilitating the absorption of carbon dioxide. It also helps to stabilize the mixture and prevent the degradation of calcium hydroxide.
**Option C:** Potassium hydroxide is not a typical component of soda lime, but it can be used as a substitute for sodium hydroxide in some cases. However, it is not a standard constituent of soda lime.
**Clinical Pearl / High-Yield Fact**
It's essential to note that soda lime can undergo a process called "carbon dioxide poisoning" if it is not properly maintained or replaced. This occurs when the soda lime becomes exhausted and is unable to absorb carbon dioxide, leading to a buildup of carbon dioxide in the anesthesia system.
**Correct Answer:** D. Calcium chloride.