IUPAC nomenclature of
`CH_3-underset(CH_2-CH_3)underset(|)overset(CH_3)overset(|)C-CH=overset(CH_3)overset(|)C-CH_3` is

Options

A. 4 - ethyl -2, 4 - dimethylpent - 2 - ene
B. 2,4,4 - trimethylhex - 2- ene
C. 3,3,5 - trimethylhex -4 -ene
D. 2,2,4 - trimethylhex -3 -ene

Answer

To determine the IUPAC name of the given compound, we will follow these steps:

### Step 1: Identify the Longest Carbon Chain
First, we need to identify the longest continuous chain of carbon atoms in the structure provided.

- Count the number of carbon atoms in various possible chains.
- The longest chain found has 6 carbon atoms.

### Step 2: Number the Carbon Chain
Once we have identified the longest chain, we will number the carbon atoms starting from the end closest to the double bond.

- The numbering will be as follows:
- 1, 2, 3, 4, 5, 6

### Step 3: Identify Substituents
Next, we need to identify any substituents (branches) on the main carbon chain.

- In this case, we have:
- A methyl group (−CH₃) on the 2nd carbon.
- Two methyl groups (−CH₃) on the 4th carbon.

### Step 4: Write the Name of the Compound
Now we can write the name of the compound based on the information we have gathered.

- The base name will be derived from the longest chain, which is hexane (since there are 6 carbons).
- Since there is a double bond starting at carbon 2, we will use "hex-2-ene".
- The substituents will be added as prefixes. We have one methyl group at position 2 and two methyl groups at position 4.

### Step 5: Combine the Information
Putting all this together, we will write the full IUPAC name:

- The substituents are listed in alphabetical order with their respective positions:
- 2-methyl and 4,4-dimethyl.

Thus, the complete IUPAC name is:

**2,4,4-trimethylhex-2-ene**

### Summary of the Steps:
1. Identify the longest carbon chain (6 carbons).
2. Number the chain from the end nearest to the double bond.
3. Identify and locate the substituents.
4. Write the base name and include the substituents in the correct order.
5. Combine everything to form the final IUPAC name.