Most acidic hydrogen is present in

Options

A. `CH_(3)-overset(O)overset(||)(C)-CH_(2)-overset(O)overset(||)(C)-O-CH_(3)`
B. `CH_(3)-O-overset(O)overset(||)(C)-CH_(2)-overset(O)overset(||)(C)-O-CH_(3)`
C. `CH_(3)-overset(O)overset(||)(C)-CH_(2)-overset(O)overset(||)(C)-CH_(3)`
D. `CH_(3)-overset(O)overset(||)(C)-CH_(2)-CH_(3)`

Answer

To determine which compound has the most acidic hydrogen, we need to analyze the provided options based on the presence of electron-withdrawing groups and the structure of the compounds. Here is a step-by-step solution:

### Step 1: Understand Acidity in Organic Compounds
Acidity in organic compounds is often influenced by the presence of electron-withdrawing groups (EWGs) near the hydrogen atoms. EWGs stabilize the negative charge that results when a hydrogen atom is removed as a proton (H⁺), making the hydrogen more acidic.

### Step 2: Identify Active Methylene Groups
An active methylene group is characterized by a -CH2- group flanked by electron-withdrawing groups. In this case, the presence of carbonyl groups (C=O) on both sides of the -CH2- group will enhance the acidity of the hydrogen atoms attached to it.

### Step 3: Analyze Each Option
1. **Option A: CH3CHC11OCH2CH2C11OCH3**
- This compound has a -CH2- group but is flanked by groups that may not be strong electron-withdrawing groups. The presence of carbon chains may reduce acidity.

2. **Option B: CH2C(=O)C(=O)**
- This compound has a -CH2- group flanked by two carbonyl groups. The carbonyl groups are strong electron-withdrawing groups, which should increase the acidity of the hydrogen atoms.

3. **Option C: CH2C(=O)C(=O)CH3**
- Similar to option B, this compound has a -CH2- group flanked by two carbonyl groups. The additional methyl group does not significantly affect the acidity.

4. **Option D: CH2C(=O)**
- This compound has only one carbonyl group flanking the -CH2- group, which makes it less acidic compared to options B and C.

### Step 4: Compare the Acidity
- The most acidic hydrogen will be in the compound where the -CH2- group is flanked by the maximum number of strong electron-withdrawing groups without any electron-donating groups present.
- Between options B and C, both have two carbonyl groups, but option C has an additional methyl group which does not contribute to acidity.

### Conclusion
After analyzing all options, **Option B (CH2C(=O)C(=O))** has the most acidic hydrogen because it has two carbonyl groups pulling electron density away from the -CH2- group, maximizing the acidity.

### Final Answer
The most acidic hydrogen is present in **Option B: CH2C(=O)C(=O)**.

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