Treatment of propionadehyde with dilute NaOH gives :

Options

A. `CH_(3)CH_(2)COOCH_(2)CH_(2)CH_(3)`
B. `CH_(3)CH_(2)CHOHCH(CH_(3))CHO`
C. `CH_(3)CH_(2)CHOHCH_(2)CH_(2)CHO`
D. `CH_(3)CH_(2)COCH_(2)CH_(2)CHO`.

Explanation

To solve the question regarding the treatment of propanaldehyde with dilute NaOH, we will follow these steps:

### Step 1: Identify the Reactant
The reactant in this case is propanaldehyde, which has the chemical formula CH3CH2CHO. It is an aldehyde with a three-carbon chain.

**Hint:** Remember that propanaldehyde is the simplest aldehyde with a three-carbon chain.

### Step 2: Understand the Reaction Conditions
The question states that propanaldehyde is treated with dilute NaOH. This indicates that we are likely dealing with an aldol condensation reaction, which typically occurs in the presence of a base.

**Hint:** Aldol condensation reactions often involve the formation of β-hydroxy aldehydes or ketones.

### Step 3: Mechanism of Aldol Condensation
In aldol condensation, one molecule of the aldehyde (propanaldehyde) undergoes deprotonation by the base (NaOH) to form an enolate ion. This enolate ion then attacks the carbonyl carbon of another molecule of propanaldehyde.

**Hint:** Look for the formation of an enolate ion and its subsequent nucleophilic attack on another carbonyl compound.

### Step 4: Formation of the Aldol Product
The reaction leads to the formation of a β-hydroxy aldehyde. In this case, the product formed will be 3-hydroxybutanal (or 3-hydroxybutyraldehyde), which can be represented as:
\[ \text{CH}_3\text{CH}_2\text{CH(OH)CH}_2\text{CHO} \]

**Hint:** The product will have a hydroxyl group (-OH) and a carbonyl group (C=O) in its structure.

### Step 5: Final Product
After the formation of the aldol product, it can further dehydrate (lose water) to form an α,β-unsaturated aldehyde. However, the question specifically asks for the product of the reaction with dilute NaOH, which is the aldol product:
\[ \text{CH}_3\text{CH}_2\text{CH(OH)CH}_2\text{CHO} \]

**Hint:** The final product may not be the only product; consider the possibility of dehydration leading to a different compound.

### Conclusion
The product formed from the treatment of propanaldehyde with dilute NaOH is 3-hydroxybutanal.

**Final Answer:** The correct answer is the option corresponding to 3-hydroxybutanal.