The correct IUPAC name of `CH_3 CH(OH)CH_2CH_2COOH` is

Options

A. 4 - hydroxypentanoic acid
B. 1 - carboxy - 3 - butanoic acid
C. 1 - carboxy - 4 - butanol
D. 1 - carboxy - 2 - butanol

Answer

To determine the correct IUPAC name of the compound `CH₃CH(OH)CH₂CH₂COOH`, we will follow these steps:

### Step 1: Identify the Functional Groups
The compound contains a carboxylic acid group (-COOH) and a hydroxyl group (-OH). The presence of the carboxylic acid group indicates that this will be the principal functional group.

### Step 2: Determine the Longest Carbon Chain
We need to find the longest continuous carbon chain that includes the carboxylic acid group. In this case, the longest chain consists of 5 carbon atoms:
- CH₃ (1)
- CH (2) with -OH
- CH₂ (3)
- CH₂ (4)
- COOH (5)

### 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. The numbering will be:
1. COOH (1)
2. CH₂ (2)
3. CH (3) with -OH
4. CH₂ (4)
5. CH₃ (5)

### Step 4: Identify Substituents and Their Positions
The hydroxyl group (-OH) is located on the third carbon (C-3) of the chain.

### Step 5: Combine the Names
According to IUPAC nomenclature, we will name the compound based on the longest chain and the functional groups:
- The longest chain is a pentane (5 carbon atoms).
- The carboxylic acid functional group will be indicated by the suffix "-oic acid."
- The hydroxyl group will be indicated by the prefix "hydroxy" and its position.

Thus, the name will be: **3-hydroxypentanoic acid**.

### Final Answer
The correct IUPAC name of `CH₃CH(OH)CH₂CH₂COOH` is **3-hydroxypentanoic acid**.

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