Total number of isomeric aldehydes and ketones having the molecular formula `C_(5)H_(10)O` are.

Explanation

To find the total number of isomeric aldehydes and ketones with the molecular formula \( C_5H_{10}O \), we will systematically identify the possible structures for both aldehydes and ketones.

### Step-by-Step Solution:

1. **Identify the Functional Groups**:
- Aldehydes contain the functional group \( -CHO \).
- Ketones contain the functional group \( C=O \) (carbonyl group) located between two carbon atoms.

2. **Calculate Isomeric Aldehydes**:
- The general structure for aldehydes with 5 carbon atoms can be represented as follows:
- **Pentanal**: \( CH_3(CH_2)_3CHO \)
- **2-Methylbutanal**: \( CH_3CH(CH_3)CH_2CHO \)
- **3-Methylbutanal**: \( CH_3CH_2CH(CH_3)CHO \)
- Thus, the isomeric aldehydes are:
1. Pentanal
2. 2-Methylbutanal
3. 3-Methylbutanal
- Total aldehydes = 3

3. **Calculate Isomeric Ketones**:
- The general structure for ketones with 5 carbon atoms can be represented as follows:
- **Pentan-2-one**: \( CH_3CO(CH_2)CH_3 \)
- **Pentan-3-one**: \( CH_3(CH_2)COCH_3 \)
- **3-Pentanone**: \( CH_3CH_2C(=O)CH_2CH_3 \)
- Thus, the isomeric ketones are:
1. Pentan-2-one
2. Pentan-3-one
- Total ketones = 2

4. **Total Isomers**:
- Combine the total number of isomeric aldehydes and ketones:
- Total = Number of Aldehydes + Number of Ketones = 3 (aldehydes) + 2 (ketones) = 5

### Final Answer:
The total number of isomeric aldehydes and ketones having the molecular formula \( C_5H_{10}O \) is **5**.