Hex-2-en-4ynioic acid is :

Options

A. `CH_(3)-C-=C-CH_(2)-CH=CH-overset(O)overset(||)(C )-OH`
B. `HC-=C-CH_(2)-CH=CH-overset(O)overset(||)(C )-OH`
C. `CH_(3)-C-=C-CH=CH-CH_(2)-overset(O)overset(||)(C )-OH`
D. `CH_(3)-C-=C-CH=CH-overset(O)overset(||)(C )-OH`

Explanation

To determine the correct structure for hex-2-en-4-yne-oic acid, we will analyze the IUPAC name step by step.

### Step-by-Step Solution:

1. **Understanding the Name**: The name "hex-2-en-4-yne-oic acid" indicates that we are dealing with a carboxylic acid (due to the "oic acid" suffix) with a six-carbon chain (indicated by "hex").

2. **Identifying the Functional Group**: The "oic acid" part tells us that there is a carboxylic acid functional group (-COOH) present. This group will be at position 1 of the carbon chain.

3. **Counting the Carbons**: The "hex" prefix indicates that there are 6 carbons in the longest chain. We will number the carbon chain starting from the carboxylic acid group, which is at position 1.

4. **Identifying the Double and Triple Bonds**: The "2-en" indicates a double bond at the second carbon, and "4-yne" indicates a triple bond at the fourth carbon.

5. **Constructing the Carbon Chain**: Start with a six-carbon chain:
- C1: -COOH (carboxylic acid)
- C2: double bond
- C4: triple bond

6. **Drawing the Structure**:
- The structure can be drawn as follows:
- C1: COOH
- C2: C=C (double bond)
- C3: C (single bond)
- C4: C≡C (triple bond)
- C5: C
- C6: C

7. **Final Structure**: The final structure of hex-2-en-4-yne-oic acid is:
```
HOOC-CH=CH-C≡C-CH2-CH3
```

8. **Choosing the Correct Option**: After analyzing the given options (A, B, C, D), we find that option D matches the structure we derived.

### Final Answer:
The correct structure for hex-2-en-4-yne-oic acid is represented by option D.

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