The correct IUPAC name of the compound `CH_3CH(C_2H_5)CH_2CH(OH)CH_3` is

Options

A. 2-Ethyl-4-pentanol
B. 2-Hydroxy-4-methyl pentane
C. 4-Ethyl-2-pentanol
D. 4-Methyl-2-hexanol

Explanation

To determine the correct IUPAC name of the compound `CH_3CH(C_2H_5)CH_2CH(OH)CH_3`, we will follow these steps:

### Step 1: Write the Structural Formula
We start by converting the condensed formula into a structural formula. The compound can be broken down as follows:
- The first carbon is `CH3` (methyl group).
- The second carbon is `CH(C2H5)`, which means it has an ethyl group (`C2H5` or `CH2CH3`) attached to it.
- The next carbon is `CH2`.
- The fourth carbon is `CH(OH)`, which indicates a hydroxyl group (-OH) is attached to it.
- Finally, the last carbon is `CH3` (methyl group).

The structural formula can be represented as:
```
CH3
|
CH3-CH-CH2-CH-CH3
|
OH
```

### Step 2: Identify the Longest Carbon Chain
Next, we need to identify the longest continuous carbon chain in the structure. By counting the carbons:
- From the leftmost `CH3` to the rightmost `CH3`, we can count a total of 6 carbons.

### Step 3: Number the Carbon Chain
We will number the carbon chain to give the functional group (hydroxyl group) the lowest possible locant:
- If we number from the left, the hydroxyl group is on carbon 4.
- If we number from the right, the hydroxyl group is on carbon 2.

Since we want the lowest locant for the hydroxyl group, we will number from the right:
1. C1 (CH3)
2. C2 (CH with OH)
3. C3 (CH2)
4. C4 (CH)
5. C5 (C2H5)
6. C6 (CH3)

### Step 4: Determine the Parent Name
The longest carbon chain has 6 carbons, which corresponds to the prefix "hex". Since the compound is an alcohol (due to the -OH group), we will use the suffix "-ol". Therefore, the base name is "hexanol".

### Step 5: Assign the Locant for the Hydroxyl Group
The hydroxyl group is on carbon 2, so we will indicate this in the name:
- The name becomes "2-hexanol".

### Step 6: Identify and Name the Substituents
Now, we need to identify any substituents:
- There is a methyl group (CH3) on carbon 4.

### Step 7: Combine the Names
To combine the names, we place the substituent name before the parent name:
- The substituent is "4-methyl" and the parent name is "2-hexanol".

### Final IUPAC Name
Putting it all together, the correct IUPAC name for the compound is:
**4-methyl-2-hexanol**