In the following reactions. Identify the compounds A, B, C and D
`PCl_(5)+SO_(2)toA+B`
`A+CH_(3)COOHtoC+SO_(2)+HCl`
`2C+(CH_(3))_(2)Cdrarr2D+CdCl_(2)`

Options

A. `SOCl_(2), POCl_(3), CH_(3)COCl, CH_(3)COCH_(3)`
B. `SOCl_(2), HCl, CH_(3)Cl, CH_(3)CHO`
C. `SO_(2),Cl_(2),C_(2)H_(5),Cl, CH_(3)COCH_(3)`
D. None of these

Answer

To solve the problem step by step, we will identify the compounds A, B, C, and D based on the given reactions.

### Step 1: Identify Compounds A and B from the Reaction of PCl₅ and SO₂
The first reaction is:
\[ \text{PCl}_5 + \text{SO}_2 \rightarrow A + B \]

- **Analysis**: Phosphorus pentachloride (PCl₅) reacts with sulfur dioxide (SO₂). In this reaction, PCl₅ acts as a nucleophile, while SO₂ acts as an electrophile.
- **Mechanism**: The chlorine atoms from PCl₅ will interact with SO₂, leading to the formation of thionyl chloride (SOCl₂) and phosphorus oxychloride (POCl₃).

Thus, we can identify:
- **Compound A**: SOCl₂ (thionyl chloride)
- **Compound B**: POCl₃ (phosphorus oxychloride)

### Step 2: Identify Compound C from the Reaction of A with Acetic Acid
The second reaction is:
\[ A + \text{CH}_3\text{COOH} \rightarrow C + \text{SO}_2 + \text{HCl} \]

- **Analysis**: Here, thionyl chloride (SOCl₂) reacts with acetic acid (CH₃COOH).
- **Mechanism**: In this reaction, one of the chlorine atoms in SOCl₂ is replaced by the hydroxyl group from acetic acid, producing acetyl chloride (CH₃COCl), along with the byproducts sulfur dioxide (SO₂) and hydrochloric acid (HCl).

Thus, we can identify:
- **Compound C**: CH₃COCl (acetyl chloride)

### Step 3: Identify Compound D from the Reaction of C with Dimethyl Cadmium
The third reaction is:
\[ 2C + (CH₃)_2\text{Cd} \rightarrow 2D + \text{CdCl}_2 \]

- **Analysis**: Acetyl chloride (C) reacts with dimethyl cadmium ((CH₃)₂Cd).
- **Mechanism**: In this reaction, the chlorine atom in acetyl chloride is replaced by a methyl group from dimethyl cadmium, leading to the formation of acetone (D).

Thus, we can identify:
- **Compound D**: Acetone (CH₃COCH₃)

### Summary of Identified Compounds
- **A**: SOCl₂ (thionyl chloride)
- **B**: POCl₃ (phosphorus oxychloride)
- **C**: CH₃COCl (acetyl chloride)
- **D**: CH₃COCH₃ (acetone)

### Final Answer
- A = SOCl₂
- B = POCl₃
- C = CH₃COCl
- D = CH₃COCH₃