Name of the compound
` H_3 C - underset(CH_3)underset(|) overset(CH_3) overset(|) C- CH =CH_2`
as per IUPAC system is

Options

A. 3, 3, 3-trimethyl-1-propane
B. 1, 1, 1-trimethyl-3-propanone
C. 3, 3-dimethylbut-1-ene
D. 1, 1-dimethyl-3-butene.

Explanation

To name the compound `H₃C - CH(CH₃) - C(CH₃) - CH=CH₂` as per the IUPAC system, we can follow these steps:

### Step 1: Identify the Longest Carbon Chain
The first step in naming an organic compound is to identify the longest continuous carbon chain that includes the functional groups (in this case, the double bond).

- In this compound, the longest carbon chain that includes the double bond is:
```
CH3 - C - C - CH = CH2
```
This chain consists of 4 carbon atoms.

### Step 2: Number the Carbon Chain
Next, we need to number the carbon chain. The numbering should be done in such a way that the double bond gets the lowest possible number.

- Starting from the end of the chain nearest to the double bond:
```
1 2 3 4
CH2 = C - C - C
```

### Step 3: Identify Substituents
Now, we need to identify any substituents attached to the main carbon chain.

- In this case, there are two methyl (CH₃) groups attached to the second and third carbon atoms.

### Step 4: Combine the Information
Now we can combine the information to write the name of the compound:

- The main chain is a butene (4 carbon atoms with a double bond).
- The double bond is between carbon 1 and carbon 2.
- There are two methyl substituents on carbon 3.

### Step 5: Write the IUPAC Name
Putting it all together, the IUPAC name of the compound is:

**3,3-Dimethylbut-1-ene**

### Summary
The final name of the compound is **3,3-Dimethylbut-1-ene**.

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