When `HgI_(2)` is added to aqueous solution of KI, which of the following are not correct statements

Options

A. Freezing point is raised
B. Freezing point does not change
C. Freezing point is lowered
D. Boiling point does not change

Explanation

To solve the question regarding the addition of `HgI2` to an aqueous solution of `KI`, we need to analyze the effects on the freezing point and boiling point of the solution.

### Step-by-Step Solution:

1. **Understanding Freezing Point Depression**:
- The freezing point depression can be calculated using the formula:
\[ \Delta T_f = i \cdot K_f \cdot m \]
where:
- \( \Delta T_f \) = depression in freezing point
- \( i \) = van 't Hoff factor (number of particles the solute breaks into)
- \( K_f \) = freezing point depression constant
- \( m \) = molality of the solution

2. **Determining the Reaction**:
- When `HgI2` is added to `KI`, it reacts to form `K2HgI4`:
\[ HgI_2 + 2KI \rightarrow K_2HgI_4 \]
- This reaction indicates that `HgI2` combines with `KI` to form a complex, which affects the number of particles in the solution.

3. **Analyzing the Van 't Hoff Factor (i)**:
- In this case, the van 't Hoff factor \( i \) for the resulting solution will be less than that of the individual ions from `KI` and `HgI2` because they form a complex.
- For `KI`, when it dissociates, it gives 3 particles (2 K⁺ and 1 I₂). However, when combined with `HgI2`, the effective number of particles is reduced.

4. **Effect on Freezing Point**:
- Since the van 't Hoff factor \( i \) decreases due to the formation of the complex, the depression in freezing point \( \Delta T_f \) will also decrease.
- Therefore, the freezing point of the solution will **not be raised** and will actually be **lowered** compared to pure solvent.

5. **Analyzing the Options**:
- **Option 1**: "Freezing point is raised" - **Incorrect** (freezing point is lowered).
- **Option 2**: "Freezing point does not change" - **Incorrect** (freezing point does change).
- **Option 3**: "Freezing point is lowered" - **Correct** (this is true).
- **Option 4**: "Boiling point does not change" - **Incorrect** (boiling point will change as well).

### Conclusion:
The statements that are **not correct** are:
- Option 1: Freezing point is raised.
- Option 2: Freezing point does not change.
- Option 4: Boiling point does not change.

### Final Answer:
The answer will be **2, 3, and 4**.

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