Which of the following molecular belongs to alkyne series?

Options

A. `C_(7)H_(18)`
B. `C_(10)H_(22)`
C. `C_(9)H_(16)`
D. `C_(16)H_(32)`

Answer

To determine which of the given molecular formulas belongs to the alkyne series, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the General Formula for Alkynes**:
The general formula for alkynes is \( C_nH_{2n-2} \), where \( n \) is the number of carbon atoms.

2. **Analyze Each Molecular Formula**:
We will check each molecular formula provided to see if it fits the alkyne formula.

3. **Check the First Option: \( C_7H_{18} \)**:
- Here, \( n = 7 \).
- According to the alkyne formula:
\[ H = 2n - 2 = 2(7) - 2 = 14 - 2 = 12 \]
- The given hydrogen count is 18, which does not match 12.
- **Conclusion**: This option does not belong to the alkyne series.

4. **Check the Second Option: \( C_{10}H_{22} \)**:
- Here, \( n = 10 \).
- According to the alkyne formula:
\[ H = 2n - 2 = 2(10) - 2 = 20 - 2 = 18 \]
- The given hydrogen count is 22, which does not match 18.
- **Conclusion**: This option does not belong to the alkyne series.

5. **Check the Third Option: \( C_9H_{16} \)**:
- Here, \( n = 9 \).
- According to the alkyne formula:
\[ H = 2n - 2 = 2(9) - 2 = 18 - 2 = 16 \]
- The given hydrogen count is 16, which matches 16.
- **Conclusion**: This option belongs to the alkyne series.

6. **Check the Fourth Option: \( C_{16}H_{32} \)**:
- Here, \( n = 16 \).
- According to the alkyne formula:
\[ H = 2n - 2 = 2(16) - 2 = 32 - 2 = 30 \]
- The given hydrogen count is 32, which does not match 30.
- **Conclusion**: This option does not belong to the alkyne series.

7. **Final Answer**:
The molecular formula that belongs to the alkyne series is \( C_9H_{16} \).