When chlorine `(Cl_(2))` water in excess is added to a salt solution containing chloroform, chloroform layer turns pale yellow.Salt contains:

Options

A. `Br^(-)`
B. `I^(-)`
C. `NO_(3)^(-)`
D. `S^(2-)`

Answer

To determine the radical present in the salt solution that causes the chloroform layer to turn pale yellow when chlorine water is added, we can follow these steps:

### Step 1: Understand the Reaction
Chlorine water (Cl₂ in water) is a strong oxidizing agent. When added to a solution containing certain halides, it can displace them and form halogen gases.

### Step 2: Identify the Halides
The possible halides that could be present in the salt solution include:
- Chloride (Cl⁻)
- Bromide (Br⁻)
- Iodide (I⁻)

### Step 3: Analyze the Reaction with Chloroform
Chloroform (CHCl₃) is a non-polar solvent. When chlorine water is added to a solution containing halides, the halides can react with chlorine. The reaction of chlorine with bromide ions (Br⁻) is particularly relevant here.

### Step 4: Reaction of Chlorine with Bromide
When chlorine water is added to a solution containing bromide ions, the following reaction occurs:
\[ \text{Cl}_2 + 2 \text{Br}^- \rightarrow 2 \text{Cl}^- + \text{Br}_2 \]
This reaction shows that bromide ions are oxidized to bromine (Br₂), while chlorine is reduced to chloride ions (Cl⁻).

### Step 5: Formation of Pale Yellow Color
Bromine (Br₂) is a brownish-yellow liquid, and when it dissolves in chloroform, it imparts a pale yellow color to the chloroform layer. This is the key observation in the question.

### Step 6: Conclusion
Since the chloroform layer turns pale yellow upon the addition of chlorine water, it indicates the presence of bromide ions in the salt solution. Therefore, the salt contains bromide ions (Br⁻).

### Final Answer
The salt contains bromide ions (Br⁻).

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