The IUPAC name of the compound having the formula is
`H_3C-underset(CH_3)underset(|)overset(CH_3)overset(|)C-CH=CH_2`

Options

A. 3,3,3 - Trimethyl -1-propene
B. 1,1,1 - Trimethyl -2-propene
C. 3,3 - Dimethyl -1-butene
D. 2,2-Dimethyl -3-butene

Answer

To determine the IUPAC name of the compound with the formula given as `H3C-(CH3)-C(=CH2)`, we will follow these steps:

### Step 1: Identify the Longest Carbon Chain
First, we need to identify the longest continuous carbon chain in the compound. The structure can be visualized as:
```
CH3
|
CH3-C=CH2
```
The longest chain here consists of 4 carbon atoms.

### Step 2: Number the Carbon Chain
We will number the carbon chain starting from the end closest to the double bond to give it the lowest possible number. The numbering will be as follows:
1. C1: CH3 (methyl group)
2. C2: CH
3. C3: C (double bond)
4. C4: CH2

### Step 3: Identify Substituents
Next, we need to identify any substituents on the main carbon chain. In this case, there are two methyl groups attached to C3.

### Step 4: Write the IUPAC Name
Now we can write the IUPAC name based on the information gathered:
- The longest chain is butene (4 carbons with a double bond).
- The double bond is located between C1 and C2, so it is 1-butene.
- There are two methyl groups on C3, which we denote as 3,3-dimethyl.

Combining these, the full IUPAC name is **3,3-dimethyl-1-butene**.

### Step 5: Verify the Name
Finally, we can verify the name by checking the structure against the name:
- The longest chain is indeed 4 carbons (butene).
- The double bond is correctly placed at C1.
- The two methyl groups are correctly identified at C3.

Thus, the IUPAC name of the compound is **3,3-dimethyl-1-butene**.

---