In palmitic acid and arachidonic acid, number of carbon atoms are respectively:

Options

A. 18, 16
B. 16, 20
C. 20, 22
D. 18, 22

Answer

To solve the question regarding the number of carbon atoms in palmitic acid and arachidonic acid, let's break it down step by step.

### Step-by-Step Solution:

1. **Identify the Fatty Acids**:
- We have two fatty acids to consider: palmitic acid and arachidonic acid.

2. **Determine the Structure of Palmitic Acid**:
- Palmitic acid is a saturated fatty acid.
- The chemical formula for palmitic acid is \( C_{16}H_{32}O_2 \).
- This indicates that there are 16 carbon atoms in palmitic acid.

3. **Determine the Structure of Arachidonic Acid**:
- Arachidonic acid is an unsaturated fatty acid.
- The chemical formula for arachidonic acid is \( C_{20}H_{32}O_2 \).
- This indicates that there are 20 carbon atoms in arachidonic acid.

4. **Summarize the Findings**:
- Therefore, the number of carbon atoms in palmitic acid is 16 and in arachidonic acid is 20.

5. **Final Answer**:
- The number of carbon atoms in palmitic acid and arachidonic acid are respectively 16 and 20.