Which one of the following will most readily be dehydrated in acidic condition?

Options

A. a.
B. b.
C. c.
D. d.

Explanation

To determine which compound will most readily be dehydrated in acidic conditions, we need to analyze the acidity of the hydrogen atoms present in the compounds. Dehydration involves the removal of a water molecule (H2O), which typically occurs by removing a hydrogen atom (H) and a hydroxyl group (OH) from adjacent carbon atoms. The hydrogen that is more acidic will facilitate this process more readily.

### Step-by-Step Solution:

1. **Understanding Dehydration**:
- Dehydration is the removal of a water molecule (H2O) from a compound. In organic chemistry, this usually involves the removal of an acidic hydrogen (H) and a hydroxyl group (OH) from adjacent carbon atoms.

2. **Identifying Acidic Hydrogens**:
- The acidity of hydrogen atoms can be influenced by the presence of electron-withdrawing groups. Such groups stabilize the negative charge that forms when the hydrogen is removed, making it easier to lose.

3. **Analyzing the Given Compounds**:
- Examine each compound to identify the presence of acidic hydrogens and any electron-withdrawing groups that may enhance their acidity.

4. **Compound A**:
- This compound has an electron-withdrawing group attached, which increases the acidity of the hydrogen. The hydrogen in this compound is likely to be the most acidic.

5. **Compound B**:
- This compound has an ethyl group, which does not enhance the acidity of the hydrogen, making it less likely to dehydrate readily.

6. **Compound C**:
- Similar to compound B, this compound lacks a strong electron-withdrawing group to increase the acidity of the hydrogen.

7. **Compound D**:
- Although this compound has an electron-withdrawing group, its distance from the acidic hydrogen reduces its effect, making it less acidic compared to compound A.

8. **Conclusion**:
- Based on the analysis, compound A has the most acidic hydrogen due to the presence of an electron-withdrawing group. Therefore, it will most readily undergo dehydration in acidic conditions.

### Final Answer:
The compound that will most readily be dehydrated in acidic conditions is **option A** (the beta hydroxy aldehyde or ketone with the most acidic hydrogen).