From the organic compounds given below, choose one compound in case which relates to the description
[Ethyne, ethanol, acetic acid, ethene]
An organic compound whose functional group is carboxyl.

Explanation

To solve the question of identifying the organic compound with a carboxyl functional group from the given options (ethyne, ethanol, acetic acid, ethene), we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Functional Groups**:
- The carboxyl functional group is represented as -COOH. It consists of a carbon atom double-bonded to an oxygen atom (C=O) and also bonded to a hydroxyl group (-OH).

2. **Analyze Each Compound**:
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