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),(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 solve the given conversion step by step, we will identify the reagents needed for each transformation.

### Step 1: Conversion of CH₃COCl to CH₃CHO
The first conversion is from acetyl chloride (CH₃COCl) to acetaldehyde (CH₃CHO). This transformation can be achieved using the reagent **Pd/BaSO₄**, which is a catalyst used in the Poisson's reaction.

**Reagent X:** Pd/BaSO₄

### Step 2: Conversion of CH₃CHO to CH₃-CHOH-CH₂CHO
Next, we need to convert acetaldehyde (CH₃CHO) to a compound that has both an alcohol and an aldehyde functional group, specifically CH₃-CHOH-CH₂CHO. This can be done by treating the aldehyde with **NaOH** (sodium hydroxide), which will lead to the formation of a β-hydroxy aldehyde through an aldol reaction.

**Reagent Y:** NaOH

### Step 3: Conversion of CH₃-CHOH-CH₂CHO to CH₃CH=CHCHO
In the final step, we need to convert the β-hydroxy aldehyde (CH₃-CHOH-CH₂CHO) to an α,β-unsaturated aldehyde (CH₃CH=CHCHO). This can be accomplished by heating the compound, which will lead to dehydration (removal of water) and formation of the double bond.

**Reagent Z:** Heat

### Summary of Reagents
- **Reagent X:** Pd/BaSO₄
- **Reagent Y:** NaOH
- **Reagent Z:** Heat

### Final Answer
The complete sequence of reagents for the conversions is:
- X: Pd/BaSO₄
- Y: NaOH
- Z: Heat