The correct order for acid strength of compounds
`CH-=CH,CH_(3)-C-=CH and CH_(2)=CH_(2)`

Answer

To determine the correct order of acid strength for the compounds CH≡CH (ethyne), CH3C≡CH (propyne), and CH2=CH2 (ethylene), we need to analyze the hybridization and the effects of substituents on acidity.

### Step-by-Step Solution:

1. **Identify the Hybridization**:
- For CH≡CH (ethyne), both carbon atoms are involved in a triple bond, which means they are sp hybridized.
- For CH3C≡CH (propyne), the terminal carbon (the one with the hydrogen) is also sp hybridized, while the carbon with the methyl group (CH3) is sp² hybridized.
- For CH2=CH2 (ethylene), both carbon atoms are involved in a double bond, which means they are sp² hybridized.

2. **Determine the Acidic Strength Based on Hybridization**:
- The acidity of hydrocarbons is influenced by the hybridization of the carbon atom bonded to the acidic hydrogen. The order of acidity based on hybridization is: sp > sp² > sp³.
- Since CH≡CH and CH3C≡CH both have sp hybridization, they are expected to be more acidic than CH2=CH2, which has sp² hybridization.

3. **Consider the Electron-Donating Effects**:
- In CH3C≡CH, the presence of the CH3 group (a +I effect) donates electron density to the carbon atom, making it less acidic compared to CH≡CH, which does not have any electron-donating groups.
- Therefore, CH≡CH will be more acidic than CH3C≡CH.

4. **Final Order of Acid Strength**:
- Based on hybridization and the electron-donating effects, we can conclude the order of acidity:
- CH≡CH (ethyne) > CH3C≡CH (propyne) > CH2=CH2 (ethylene).

### Conclusion:
The correct order for the acid strength of the compounds is:
**CH≡CH > CH3C≡CH > CH2=CH2**