Write IUPAC name of `Cl-CH_(2)-CH_(2)-COOH`.

Explanation

To determine the IUPAC name of the compound `Cl-CH₂-CH₂-COOH`, we will follow these steps:

### Step 1: Identify the longest carbon chain
The compound has a total of three carbon atoms in a straight chain, which can be represented as follows:
- CH₂ (1st carbon)
- CH₂ (2nd carbon)
- COOH (3rd carbon, which is the carboxylic acid group)

### Step 2: Determine the functional group
The functional group present in this compound is the carboxylic acid group (-COOH). This group is the principal functional group for naming.

### Step 3: Number the carbon chain
We will number the carbon chain starting from the end closest to the carboxylic acid group to give it the lowest possible number. Thus, the numbering will be:
- Carbon 1: COOH (carboxylic acid)
- Carbon 2: CH₂
- Carbon 3: CH₂ (with Cl)

### Step 4: Identify substituents
In this compound, there is a chlorine (Cl) substituent attached to the third carbon.

### Step 5: Combine the information for the IUPAC name
Now we can combine the information:
- The longest chain has three carbon atoms, which is called "propane."
- The chlorine substituent is at position 3, so we will use the prefix "3-chloro."
- Since the carboxylic acid group is at position 1, we will use "propanoic acid" as the base name.

### Final IUPAC Name
Putting it all together, the IUPAC name of the compound is **3-chloropropanoic acid**.

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