In the given reaction
`CH_(3)-CHO overset(2HCHO //dil.Na_2CO_3)(rarr)(X)`, 'X' will be

Options

A. `HOCH_2-CH_2-CHO`
B. `HOCH_2-overset(CH_2OH)overset(|)(C )H-CHO`
C. `HOCH_2-underset(CH_2OH)underset(|)overset(CH_2OH)overset(|)(C )-CHO`
D. `HOCH_2-underset(CH_2OH)underset(|)overset(CH_2OH)overset(|)(C )-CH_2OH`

Answer

To solve the question regarding the reaction of CH₃CHO with dilute sodium carbonate (Na₂CO₃), we need to understand the mechanism involved in this reaction. Here’s a step-by-step breakdown of the process:

### Step 1: Identify the Reactants
The reactant in this reaction is CH₃CHO (acetaldehyde). We are also using dilute sodium carbonate (Na₂CO₃) which acts as a mild base.

**Hint:** Recognize the structure of acetaldehyde and the role of sodium carbonate in the reaction.

### Step 2: Understand the Role of Sodium Carbonate
Sodium carbonate (Na₂CO₃) dissociates in solution to give carbonate ions (CO₃²⁻). These carbonate ions can act as a base and abstract a proton (H⁺) from the aldehyde group of CH₃CHO.

**Hint:** Consider how the base interacts with the aldehyde functional group.

### Step 3: Formation of Enolate Ion
When the base abstracts a proton from the aldehyde, it forms an enolate ion. The structure of the enolate ion will have a negative charge on the carbon adjacent to the carbonyl group.

**Hint:** Draw the structure of the enolate ion formed after deprotonation.

### Step 4: Nucleophilic Attack
The enolate ion can now act as a nucleophile and attack another molecule of CH₂O (formaldehyde). This leads to the formation of a new carbon-carbon bond.

**Hint:** Visualize how the enolate ion attacks the carbonyl carbon of formaldehyde.

### Step 5: Formation of a β-Hydroxy Aldehyde
After the nucleophilic attack, the resulting structure will be a β-hydroxy aldehyde. This compound will have both a hydroxyl group (-OH) and an aldehyde group (-CHO).

**Hint:** Identify the new functional groups present in the product.

### Step 6: Final Product Identification
The final product after the reaction will be a compound that has two hydroxyl groups and one aldehyde group, which can be represented as CH₂(OH)CH(OH)CHO. This compound is known as a diol with an aldehyde.

**Hint:** Confirm the structure and name of the final product based on the functional groups present.

### Conclusion
The final product 'X' in the reaction CH₃CHO + HCHO in the presence of dilute Na₂CO₃ is a β-hydroxy aldehyde, specifically 3-hydroxybutanal.

**Final Answer:** The product 'X' will be 3-hydroxybutanal (or a similar structure depending on how the reaction proceeds).