`C_(5)H_(10)O` is carbonyl compound. The number of structural isomers possible for this molecular formula are

Options

A. 5
B. 8
C. 6
D. 7

Answer

To determine the number of structural isomers for the carbonyl compound with the molecular formula \( C_5H_{10}O \), we need to consider the types of carbonyl compounds it can form, which are aldehydes and ketones.

### Step-by-Step Solution:

1. **Identify the Type of Carbonyl Compound**:
- The compound \( C_5H_{10}O \) can be either an aldehyde or a ketone.

2. **Count the Aldehyde Isomers**:
- **Aldehyde Structure**: Aldehydes have the general structure \( RCHO \) where \( R \) is a hydrocarbon chain.
- For \( C_5H_{10}O \):
- **Straight-chain Aldehyde**: \( CH_3(CH_2)_3CHO \) (Pentanal)
- **Branched-chain Aldehydes**:
1. \( CH_3CH(CH_3)CH_2CHO \) (2-Methylbutanal)
2. \( CH_3CH_2CH(CH_3)CHO \) (3-Methylbutanal)
3. \( (CH_3)_2CHCH_2CHO \) (2-Methylbutanal)
- Total Aldehyde Isomers: 4

3. **Count the Ketone Isomers**:
- **Ketone Structure**: Ketones have the general structure \( RC(=O)R' \).
- For \( C_5H_{10}O \):
- **Straight-chain Ketone**: \( CH_3(CH_2)_3C(=O)CH_3 \) (Pentan-2-one)
- **Branched-chain Ketones**:
1. \( CH_3C(=O)CH_2CH_2CH_3 \) (Butan-2-one)
2. \( CH_3C(=O)CH(CH_3)CH_2CH_3 \) (3-Pentanone)
- Total Ketone Isomers: 3

4. **Total Structural Isomers**:
- Combine the total number of isomers from both aldehydes and ketones:
- Total Isomers = Aldehydes (4) + Ketones (3) = 7

### Final Answer:
The total number of structural isomers possible for the molecular formula \( C_5H_{10}O \) is **7**.

---