Select odd one out in the `C_2H_2, C_3H_4, C_3H_8, C_4H_6`

Explanation

To solve the problem of selecting the odd one out from the given hydrocarbons \(C_2H_2, C_3H_4, C_3H_8, C_4H_6\), we will analyze each compound based on its classification as alkane, alkene, or alkyne.

### Step-by-Step Solution:

1. **Identify the Type of Each Hydrocarbon**:
- **C2H2**: This compound has the formula for alkynes, which is \(C_nH_{2n-2}\). For \(n=2\), we have \(C_2H_{2(2)-2} = C_2H_2\).
- **C3H4**: This also fits the alkyne formula. For \(n=3\), we have \(C_3H_{2(3)-2} = C_3H_4\).
- **C3H8**: This compound fits the alkane formula, which is \(C_nH_{2n+2}\). For \(n=3\), we have \(C_3H_{2(3)+2} = C_3H_8\).
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