Fill in the reagents for the given conversion :
`CH_(3)COCl overset((X))to CH_(3)CHO overset((Y))to CH_(3)-overset(OH) overset(|)(CH)-CH_(2)CHO overset((Z))to CH_(3)CH=CHCHO`

Options

A. `{:(X,Y,Z),(H_2//Pd//BaSO_(4),"dil. "NaOH, "heat") :}`
B. `{:(X,Y,Z),(NaOH,"Hydrolysis","heat"):}`
C. `{:(X,Y,Z),(I_(2)//NaOH,LiAlH_(4), H_(3)O^(+)):}`
D. `{:(X,Y,Z),(CrO_(3),"Warm",CO_(2)):}`

Answer

To fill in the reagents for the given conversion, we will analyze each step of the reaction sequence.

### Step 1: Conversion of Acetyl Chloride to Acetaldehyde
**Reaction:**
\[ \text{CH}_3\text{COCl} \xrightarrow{(X)} \text{CH}_3\text{CHO} \]

**Reagent (X):**
The conversion of acetyl chloride (CH₃COCl) to acetaldehyde (CH₃CHO) can be achieved through the Rosenmund reduction. The reagent used for this reaction is:
\[ \text{H}_2 \text{(g)}, \text{Pd/BaSO}_4 \]
This is a catalytic hydrogenation process where palladium on barium sulfate acts as a catalyst in the presence of hydrogen gas.

### Step 2: Conversion of Acetaldehyde to Beta-Hydroxy Carbonyl Compound
**Reaction:**
\[ \text{CH}_3\text{CHO} \xrightarrow{(Y)} \text{CH}_3\text{CH(OH)CH}_2\text{CHO} \]

**Reagent (Y):**
The conversion of acetaldehyde to a beta-hydroxy carbonyl compound is done through an aldol condensation reaction. The reagent used for this reaction is:
\[ \text{Dilute NaOH} \]
This base facilitates the deprotonation of the alpha hydrogen, leading to the formation of an enolate ion, which then reacts with another molecule of acetaldehyde.

### Step 3: Conversion of Beta-Hydroxy Carbonyl Compound to Alpha, Beta-Unsaturated Carbonyl Compound
**Reaction:**
\[ \text{CH}_3\text{CH(OH)CH}_2\text{CHO} \xrightarrow{(Z)} \text{CH}_3\text{CH=CHCHO} \]

**Reagent (Z):**
The conversion of the beta-hydroxy carbonyl compound to an alpha, beta-unsaturated carbonyl compound involves dehydration (removal of water). The reagent typically used for this step is:
\[ \text{Heat} \]
Heating the beta-hydroxy carbonyl compound promotes the elimination of water, resulting in the formation of the double bond.

### Summary of Reagents:
- **(X)**: H₂ (g), Pd/BaSO₄
- **(Y)**: Dilute NaOH
- **(Z)**: Heat

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