In which of the following molecule hydrogen is more acidic ?

Options

A. Acetylene
B. Methane
C. Ethylene oxide
D. Ethane

Explanation

To determine which molecule has the most acidic hydrogen among acetylene, methane, ethylene oxide, and ethane, we will analyze the structures and the factors that influence acidity.

### Step-by-Step Solution:

1. **Identify the Structures of the Molecules**:
- **Acetylene (C2H2)**: This molecule has a triple bond between the two carbon atoms, with each carbon bonded to one hydrogen atom. The structure is: H-C≡C-H.
- **Methane (CH4)**: Methane has a single carbon atom bonded to four hydrogen atoms. The structure is: H
|
H-C-H
|
H.
- **Ethylene Oxide (C2H4O)**: This is a cyclic ether with two carbon atoms and one oxygen atom. The structure is:
```
O
/ \
C C
/ \
H H
```
- **Ethane (C2H6)**: Ethane consists of two carbon atoms each bonded to three or two hydrogen atoms. The structure is:
```
H H
| |
H-C-C-H
| |
H H
```

2. **Determine the Acidity of Hydrogen Atoms**:
- The acidity of hydrogen atoms in organic compounds is influenced by the stability of the conjugate base formed after deprotonation (removal of H+).
- The more electronegative atoms or groups attached to the carbon atom can stabilize the negative charge of the conjugate base, making the hydrogen more acidic.

3. **Analyze Each Compound**:
- **Acetylene**: The hydrogen atoms are attached to sp-hybridized carbons, which have a higher electronegativity than sp2 or sp3 hybridized carbons. However, there are no electronegative atoms nearby to stabilize the conjugate base.
- **Methane**: The hydrogen atoms are attached to sp3-hybridized carbon, which is the least acidic due to the lack of electronegative atoms.
- **Ethylene Oxide**: The presence of oxygen (an electronegative atom) adjacent to the carbon atoms increases the acidity of the hydrogen atoms. The conjugate base formed after deprotonation is stabilized by the electronegative oxygen.
- **Ethane**: Similar to methane, the hydrogen atoms are attached to sp3-hybridized carbons and lack electronegative atoms to stabilize the conjugate base.

4. **Conclusion**:
- Among the four molecules, **ethylene oxide** has the most acidic hydrogen due to the presence of the electronegative oxygen atom, which stabilizes the conjugate base formed upon deprotonation.

### Final Answer:
The molecule in which hydrogen is more acidic is **Ethylene Oxide**.