Chlorine gas is passed into a solution containing KF, Kl and KBr and `CHCl_3` is added. The initial colour in `CHCl_3` layer is

Options

A. Violet due to formation of `I_2`
B. Orange due to formation of `Br_2`
C. Colourless due to formation of `F_2`
D. No colour change due to no reaction

Answer

To solve the problem, we need to analyze the reactions that occur when chlorine gas (Cl2) is passed into a solution containing potassium fluoride (KF), potassium iodide (KI), and potassium bromide (KBr), followed by the addition of chloroform (CHCl3).

### Step-by-Step Solution:

1. **Identify the Reactions**:
- When chlorine gas is passed into the solution, it will react with the iodide ions (I-) and bromide ions (Br-) present in the solution.
- The reactions are as follows:
- For potassium iodide (KI):
\[ Cl_2 + 2KI \rightarrow 2KCl + I_2 \]
Here, iodine (I2) is produced.
- For potassium bromide (KBr):
\[ Cl_2 + 2KBr \rightarrow 2KCl + Br_2 \]
Here, bromine (Br2) is produced.

2. **Formation of Layers**:
- After the reactions, chloroform (CHCl3) is added to the solution. Chloroform is a non-polar solvent and will form a separate layer.
- Iodine (I2) is known to impart a violet color to chloroform, while bromine (Br2) imparts a brown color.

3. **Determine the Dominant Reaction**:
- Since KI reacts with Cl2 to form I2, the presence of I2 will dominate the color observed in the chloroform layer.
- The reaction with KBr will also occur, but the amount of Br2 produced will be less significant compared to the amount of I2 produced from KI.

4. **Initial Color in Chloroform Layer**:
- The initial color in the chloroform layer will be violet due to the formation of iodine (I2) from the reaction with potassium iodide (KI).

### Conclusion:
The initial color in the chloroform layer is **violet** due to the formation of iodine (I2).

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