The `IUPAC` name of `HOCH_(2)CH=C(CH_(3))_(2)` is:

Options

A. `2`-Methyl-`2`-buten `4`-ol
B. `3`-Methyl-`2`-buten `1`-ol
C. `2`-Methyl-`2`-butanol
D. `3`-Methyl-`2`-butenol

Answer

To determine the IUPAC name of the compound \( HOCH_2CH=C(CH_3)_2 \), we can follow these steps:

### Step 1: Identify the longest carbon chain
First, we need to identify the longest continuous carbon chain in the molecule. In this case, the longest chain consists of four carbon atoms.

### Step 2: Number the carbon chain
Next, we will number the carbon chain starting from the end closest to the functional group (the hydroxyl group, -OH). This will give us the following numbering:
1. \( C_1 \) - \( CH_2OH \)
2. \( C_2 \) - \( CH \)
3. \( C_3 \) - \( C \) (double bond)
4. \( C_4 \) - \( C(CH_3)_2 \)

### Step 3: Identify the functional groups and substituents
The functional group present is the hydroxyl group (-OH), which is a priority functional group. We also have a double bond between \( C_2 \) and \( C_3 \) and a methyl group (\( CH_3 \)) as a substituent on \( C_4 \).

### Step 4: Assign locants to the substituents
- The hydroxyl group is on carbon 1, so we denote it as "1-ol".
- The double bond starts at carbon 2, so we denote it as "2-".
- The methyl group is on carbon 3, so we denote it as "3-methyl".

### Step 5: Combine the information to write the IUPAC name
Now we can combine all the information:
- The base name for a four-carbon chain with a double bond is "butene".
- Since the double bond starts at carbon 2, we have "2-butene".
- The hydroxyl group is at carbon 1, so we have "1-ol".
- The methyl group at carbon 3 gives us "3-methyl".

Putting it all together, the IUPAC name of the compound is **3-methyl-2-buten-1-ol**.

### Final Answer:
**3-methyl-2-buten-1-ol**

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