Find the last product [D] in reaction sequence
`C_(6)H_(5)CHO+CH_(3)-overset(O)overset(||)C-CH_(2)-COOC_(2)H_(5)` `overset(H_3O^(+))to A overset(Delta)to C underset(OH^(-)//Delta) overset(NH_2-NH_2)to D `

Options

A. `C_(6)H_(5)-CH=Choverset(OH)overset("| ")"CH"-CH_(3)`
B. `C_(6)H_(5)-CH=CH-CH_(2)-CH_(3)`
C.
D. `C_(6)H_(5)-CH=CH-overset(O)overset(||)C-CH_(3)`

Answer

To find the last product [D] in the given reaction sequence, we will break down the process step by step.

### Step 1: Hydrolysis of the Ester
We start with the reactants:
- Benzaldehyde (C₆H₅CHO)
- Ethyl acetoacetate (CH₃COCH₂COOC₂H₅)

In the presence of an acidic medium (H₃O⁺), the ester undergoes hydrolysis. This means that the ester bond will break, and we will form an alcohol and a carboxylic acid. The hydrolysis of the ester will yield:
- Benzaldehyde remains unchanged.
- The ethyl acetoacetate will hydrolyze to form acetic acid (CH₃COOH) and ethanol (C₂H₅OH).

The product after hydrolysis will be:
- C₆H₅CHO + CH₃COOH + C₂H₅OH

### Step 2: Decarboxylation
Next, we heat the product mixture. The acetic acid can undergo decarboxylation (removal of CO₂) to form:
- Acetone (CH₃COCH₃)

So now we have:
- C₆H₅CHO + CH₃COCH₃

### Step 3: Formation of an Enol
In the next step, we have the formation of an enol. The enol will form from the reaction of benzaldehyde with acetone. The enol form will be:
- C₆H₅C(OH)=CH₂

### Step 4: Elimination of Water
Next, we will eliminate a water molecule to form an alkene. The elimination of water from the enol will yield:
- C₆H₅C=CH₂

### Step 5: Reduction with Hydrazine
Finally, we treat the product with hydrazine (NH₂-NH₂) in a basic medium. This will reduce the double bond and replace the carbonyl oxygen with hydrogen. The final product will be:
- C₆H₅CH=CHCH₃

### Final Product
The last product [D] in the reaction sequence is:
- C₆H₅CH=CHCH₃

### Summary of Steps:
1. Hydrolysis of the ester to form acetic acid and ethanol.
2. Decarboxylation of acetic acid to form acetone.
3. Formation of an enol from the reaction of benzaldehyde and acetone.
4. Elimination of water to form an alkene.
5. Reduction with hydrazine to form the final product.