The IUPAC name of `PhCH_2 CH_2 COOH `is named as

Options

A. 3-phenylpropanoic acid
B. benzylacetic acid
C. carboxyethyl benzene
D. 2-phenylpropanoic acid.

Answer

To determine the IUPAC name of the compound `PhCH₂CH₂COOH`, we will follow these steps:

### Step 1: Identify the Functional Group
The compound contains a carboxylic acid group (–COOH), which is the highest priority functional group in IUPAC nomenclature.

### Step 2: Number the Carbon Chain
We need to number the carbon chain starting from the end closest to the carboxylic acid group to give it the lowest possible number. In this case, the numbering will be as follows:

1. COOH (carbon 1)
2. CH₂ (carbon 2)
3. CH₂ (carbon 3)
4. Ph (phenyl group, which is a substituent)

### Step 3: Identify the Main Chain and Substituents
The longest carbon chain that includes the carboxylic acid is three carbons long, which corresponds to "propanoic acid". The phenyl group (Ph) is attached to the third carbon of the main chain.

### Step 4: Combine the Information
Since the phenyl group is on the third carbon, we will denote it as "3-phenyl". The main chain is "propanoic acid" due to the presence of three carbons and the carboxylic acid functional group.

### Step 5: Write the Complete IUPAC Name
Combining all the information, the IUPAC name of the compound `PhCH₂CH₂COOH` is:

**3-phenylpropanoic acid**

### Final Answer
The IUPAC name of `PhCH₂CH₂COOH` is **3-phenylpropanoic acid**.

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