`BaCl_(2)` solution gives a white precipitate with a solution of a salt, which dissolves in dilute hydrochloric acid with the evolution of colourless, pungent smelling gas. The gas as well as the salt both are used as bleaching agent in the textile industries. The salt contains :

Options

A. sulphite
B. sulphide
C. acetate
D. carbonate

Explanation

To solve the problem step by step, we need to analyze the information given in the question and apply our knowledge of chemistry.

### Step 1: Identify the precipitate formed with BaCl₂
When barium chloride (BaCl₂) is mixed with a solution containing a certain salt, a white precipitate is formed. The possible salts that can react with Ba²⁺ to form a white precipitate include sulfates (BaSO₄), carbonates (BaCO₃), and sulfites (BaSO₃).

**Hint:** Look for salts that form white precipitates with barium ions.

### Step 2: Determine the nature of the precipitate
The question states that the precipitate dissolves in dilute hydrochloric acid (HCl) with the evolution of a colorless, pungent-smelling gas. This indicates that the precipitate must be a salt that reacts with HCl to release a gas.

**Hint:** Consider the gases that are released when common salts react with acids.

### Step 3: Analyze the possible gases
The possible gases that can be released when a salt reacts with HCl include:
- Carbon dioxide (CO₂) from carbonates
- Sulfur dioxide (SO₂) from sulfites
- Hydrogen sulfide (H₂S) from sulfides

Since the gas is described as colorless and pungent, sulfur dioxide (SO₂) is a strong candidate because it is known for its characteristic smell.

**Hint:** Think about the properties of the gases produced from the reaction of salts with acids.

### Step 4: Write the reaction for the precipitate
If we assume the salt is a sulfite (SO₃²⁻), the reaction with BaCl₂ would be:
\[ \text{Ba}^{2+} + \text{SO}_3^{2-} \rightarrow \text{BaSO}_3 \, (\text{white precipitate}) \]

When BaSO₃ is treated with HCl, the reaction would be:
\[ \text{BaSO}_3 + 2\text{HCl} \rightarrow \text{BaCl}_2 + \text{SO}_2 + \text{H}_2O \]

This reaction produces sulfur dioxide (SO₂), which is colorless and has a pungent smell.

**Hint:** Write down the balanced chemical equations to confirm the identity of the gas.

### Step 5: Confirm the bleaching agents
Both the salt (sulfite) and the gas (sulfur dioxide) are known to act as bleaching agents in the textile industry. This confirms that the salt in question is indeed a sulfite.

**Hint:** Research the uses of sulfites and sulfur dioxide in industrial applications.

### Conclusion
Based on the analysis, the salt contains sulfite (SO₃²⁻), which forms a white precipitate with BaCl₂ and produces sulfur dioxide gas upon reaction with dilute hydrochloric acid.

**Final Answer:** The salt contains **sulfite (SO₃²⁻)**.