A colourless fuming liquid (A) can be prepared by passing `SO_(2)` over phosphorous pentachloride. The liquid can readily be hydrolysed to give sulphurous acid. The compound (A) is

Options

A. `SOCl_(2)`
B. `SO_(2)Cl_(2)`
C. `SCl_(2)`
D. `SCl_(4)`

Answer

To solve the problem, let's break it down step by step:

### Step 1: Identify the Reaction
We are given that a colorless fuming liquid (A) can be prepared by passing sulfur dioxide (SO₂) over phosphorus pentachloride (PCl₅).

### Step 2: Write the Reaction
The reaction between sulfur dioxide and phosphorus pentachloride can be represented as:
\[ \text{SO}_2 + \text{PCl}_5 \rightarrow \text{SOCl}_2 + \text{POCl}_3 \]
Here, SOCl₂ (thionyl chloride) is one of the products formed.

### Step 3: Analyze the Properties of the Product
The problem states that the liquid (A) can be hydrolyzed to give sulfurous acid (H₂SO₃). We need to check if SOCl₂ can be hydrolyzed to form H₂SO₃.

### Step 4: Hydrolysis of SOCl₂
When thionyl chloride (SOCl₂) is hydrolyzed, the reaction can be written as:
\[ \text{SOCl}_2 + 2\text{H}_2\text{O} \rightarrow \text{H}_2\text{SO}_3 + 2\text{HCl} \]
This confirms that hydrolysis of SOCl₂ produces sulfurous acid (H₂SO₃) and hydrochloric acid (HCl).

### Step 5: Conclusion
Since SOCl₂ can be formed from the reaction of SO₂ and PCl₅ and can be hydrolyzed to produce sulfurous acid, we conclude that the compound (A) is:
\[ \text{SOCl}_2 \]
Thus, the answer is thionyl chloride (SOCl₂).

### Final Answer
The compound (A) is SOCl₂ (thionyl chloride).

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