(X) is the product of cross aldol condensation between benzaldehyde `(C_(6)H_(5)CHO)` and acetone. What is its structure ?

Options

A. `C_(6)H_(6)-CH=CH-overset(O)overset(||)(C)-CH_(3)`
B. `C_(6)H_(5)-CH=C-(CH_(3))_(2)`
C. `C_(6)H_(5)-CO-CH_(2)-C=(CH_(3))_(2)`
D. None of these

Answer

To determine the structure of the product (X) from the cross aldol condensation between benzaldehyde (C₆H₅CHO) and acetone (C₃H₆O), we can follow these steps:

### Step 1: Identify the Reactants
- **Benzaldehyde**: C₆H₅CHO
- **Acetone**: C₃H₆O (or CH₃COCH₃)

### Step 2: Understand the Aldol Condensation Process
Aldol condensation involves the formation of a β-hydroxy aldehyde or ketone, followed by dehydration to yield an α,β-unsaturated carbonyl compound. The reaction requires at least one of the reactants to have α-hydrogens, which are present in acetone.

### Step 3: Formation of the Enolate Ion
- In the presence of a base (like NaOH), acetone can lose an α-hydrogen to form an enolate ion.
- The enolate ion is a nucleophile and can attack the carbonyl carbon of benzaldehyde.

### Step 4: Nucleophilic Attack
- The enolate ion from acetone attacks the carbonyl carbon of benzaldehyde, forming a β-hydroxy ketone.
- The structure at this stage is:
- **Intermediate**: C₆H₅C(OH)(CH₃)CH₂

### Step 5: Dehydration
- The β-hydroxy ketone undergoes dehydration (loss of water) to form the final product.
- The dehydration results in the formation of a double bond between the α and β carbons.

### Step 6: Final Product Structure
- The final product (X) is an α,β-unsaturated carbonyl compound. Its structure can be represented as:
- **Final Product**: C₆H₅C=CH₂COCH₃
- This can also be drawn as:
```
O
||
C₆H₅-C-CH=CH₂
|
CH₃
```

### Summary of the Product Structure
The product of the cross aldol condensation between benzaldehyde and acetone is known as **benzylidene acetone**, which has the structure shown above.

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