Total number of chain isomers possible for `C_(7)H_(16)` are

Answer

To determine the total number of chain isomers possible for the molecular formula \( C_7H_{16} \), we will follow a systematic approach to identify all possible structures.

### Step 1: Understand Chain Isomers
Chain isomers are compounds that have the same molecular formula but differ in the arrangement of the carbon skeleton. For \( C_7H_{16} \), we are looking for different ways to arrange 7 carbon atoms.

### Step 2: Draw the Straight-Chain Structure
The simplest structure is the straight-chain alkane, which is heptane:
- **Heptane**: \( CH_3-CH_2-CH_2-CH_2-CH_2-CH_2-CH_3 \)

### Step 3: Identify Possible Branching
Next, we will explore branching by removing one carbon from the end of the chain and adding it as a branch.

1. **2-Methylhexane**:
- Structure: \( CH_3-CH(CH_3)-CH_2-CH_2-CH_2 \)

2. **3-Methylhexane**:
- Structure: \( CH_3-CH_2-CH(CH_3)-CH_2-CH_2 \)

3. **2,2-Dimethylpentane**:
- Structure: \( CH_3-C(CH_3)_2-CH_2-CH_2 \)

4. **2,3-Dimethylpentane**:
- Structure: \( CH_3-CH(CH_3)-CH(CH_3)-CH_2 \)

5. **2,4-Dimethylpentane**:
- Structure: \( CH_3-CH(CH_3)-CH_2-CH(CH_3) \)

6. **3,3-Dimethylpentane**:
- Structure: \( CH_3-CH_2-C(CH_3)_2-CH_2 \)

7. **3-Ethylpentane**:
- Structure: \( CH_3-CH_2-CH_2-CH(CH_2CH_3)-CH_2 \)

8. **2,2,3-Trimethylbutane**:
- Structure: \( C(CH_3)_3-CH(CH_3)-CH_3 \)

### Step 4: Count the Isomers
After systematically drawing and naming all possible structures, we find the following chain isomers for \( C_7H_{16} \):
1. Heptane
2. 2-Methylhexane
3. 3-Methylhexane
4. 2,2-Dimethylpentane
5. 2,3-Dimethylpentane
6. 2,4-Dimethylpentane
7. 3,3-Dimethylpentane
8. 3-Ethylpentane
9. 2,2,3-Trimethylbutane

### Conclusion
The total number of chain isomers for \( C_7H_{16} \) is **9**.