Write the IUPAc name of the following compound :
(a) `CH_(3)-CH_(2)-overset(CH_(3))overset(|)(CH)-CH=CH-CH_(2)-CH_(3)`
(b) `CH_(3)-CH_(2)-overset(CH_(3))overset(|)(CH)-overset(CH_(2)-CH_(3))overset(|)(CH)-underset(CH_(3))underset(|)underset(CH-CH_(3))underset(|)underset(CH_(2))underset(|)underset(CH_(2))underset(|)(CH)-CH=overset(CH_(3))overset(|)(C)-CH_(3)`

Answer

To write the IUPAC names for the given compounds, we will follow a systematic approach. Let's break down the steps for each compound.

### Part (a): `CH₃-CH₂-overset(CH₃)overset(|)(CH)-CH=CH-CH₂-CH₃`

1. **Identify the Parent Chain**:
- The longest continuous carbon chain needs to be identified. In this case, the longest chain consists of 7 carbon atoms.

2. **Number the Carbon Chain**:
- Number the carbon chain from the end nearest to the double bond (alkene). The numbering will be as follows:
- 1: CH= (double bond)
- 2: CH
- 3: CH₂
- 4: CH
- 5: CH₃ (methyl branch)
- 6: CH₂
- 7: CH₃
- The numbering gives us: 1-CH, 2-CH, 3-CH₂, 4-CH, 5-CH₃, 6-CH₂, 7-CH₃.

3. **Identify the Substituents**:
- There is one methyl group on the 5th carbon.

4. **Determine the Functional Group**:
- The compound contains a double bond (alkene) located between the 2nd and 3rd carbons.

5. **Construct the IUPAC Name**:
- Combine the substituents and the parent chain with the functional group:
- The name will be: **5-methyl-3-heptene**.

### Part (b): `CH₃-CH₂-overset(CH₃)overset(|)(CH)-overset(CH₂-CH₃)overset(|)(CH)-underset(CH₃)underset(|)underset(CH-CH₃)underset(|)underset(CH₂)underset(|)underset(CH₂)underset(|)(CH)-CH=overset(CH₃)overset(|)(C)-CH₃`

1. **Identify the Parent Chain**:
- The longest continuous carbon chain must be identified. In this case, the longest chain consists of 8 carbon atoms.

2. **Number the Carbon Chain**:
- Number the carbon chain from the end nearest to the double bond. The numbering will be as follows:
- 1: CH
- 2: CH
- 3: CH₂
- 4: CH
- 5: CH₂ (ethyl branch)
- 6: CH
- 7: CH₃
- 8: CH₃
- The numbering gives us: 1-CH, 2-CH, 3-CH₂, 4-CH, 5-CH₂, 6-CH, 7-CH₃, 8-CH₃.

3. **Identify the Substituents**:
- There are ethyl and methyl groups. The methyl groups are located at the 2nd and 6th carbons.

4. **Determine the Functional Group**:
- The compound contains a double bond (alkene) located between the 2nd and 3rd carbons.

5. **Construct the IUPAC Name**:
- Combine the substituents and the parent chain with the functional group:
- The name will be: **5-ethyl-2,6-dimethyl-3-methylbut-2-ene**.

### Final IUPAC Names:
- (a) 5-methyl-3-heptene
- (b) 5-ethyl-2,6-dimethyl-3-methylbut-2-ene