The IUPAC name of the compound `CH_(2)=CH-CH(CH_(3))_(2)` is:

Options

A. (a) 1,1-Dimethylprop-2-ene
B. (b) 3-Methylbut-1-ene
C. (c) 2-Vinylpropane
D. (d) 1-Isopropylethylene

Answer

To determine the IUPAC name of the compound \( CH_2=CH-CH(CH_3)_2 \), we can follow these steps:

### Step 1: Draw the Structure
Start by drawing the structure of the compound based on the given molecular formula. The compound consists of a double bond and branching.

- The structure can be represented as:
```
CH3
|
CH2=CH-CH
|
CH3
```

### Step 2: Identify the Longest Carbon Chain
Next, identify the longest continuous carbon chain that includes the double bond.

- In this case, the longest chain consists of four carbon atoms (butane) with a double bond between the first and second carbon atoms.

### Step 3: Number the Carbon Chain
Number the carbon chain starting from the end nearest to the double bond to give the double bond the lowest possible number.

- The numbering will be as follows:
```
1 2 3 4
CH2=CH-CH-CH3
```

### Step 4: Identify Substituents
Now, identify any substituents on the main carbon chain.

- There is a methyl group (–CH3) attached to the third carbon of the main chain.

### Step 5: Write the IUPAC Name
Combine the information gathered to write the IUPAC name.

- The longest chain is butane with a double bond at position 1 (but-1-ene).
- There is a methyl group at position 3.

Thus, the IUPAC name is **3-methylbut-1-ene**.

### Final Answer
The IUPAC name of the compound \( CH_2=CH-CH(CH_3)_2 \) is **3-methylbut-1-ene**.

---