`HgI_(2)darr+2HI to K_(2)[HgI_(4)]`

Options

A. For precipitate formation formation reaction
B. For precipitate dissolution reaction
C. For precipitate exchange reaction
D. For no reaction

Answer

To solve the question regarding the chemical reaction \( \text{HgI}_2 + 2\text{HI} \rightarrow \text{K}_2[\text{HgI}_4] \), we need to analyze the nature of the reaction based on the provided options.

### Step-by-Step Solution:

1. **Identify the Reactants and Products**:
- The reactants are \( \text{HgI}_2 \) (mercury(II) iodide) and \( \text{HI} \) (hydroiodic acid).
- The product is \( \text{K}_2[\text{HgI}_4] \) (potassium tetraiodomercurate(II)).

2. **Determine the State of Reactants**:
- \( \text{HgI}_2 \) is typically a solid at room temperature and can be considered a precipitate.
- \( \text{HI} \) is a gas or can be in aqueous solution, depending on the conditions.

3. **Analyze the Reaction**:
- In this reaction, \( \text{HgI}_2 \) (the precipitate) reacts with \( \text{HI} \) to form \( \text{K}_2[\text{HgI}_4] \).
- The formation of \( \text{K}_2[\text{HgI}_4] \) indicates that the \( \text{HgI}_2 \) is dissolving in the presence of \( \text{HI} \) to form a soluble complex.

4. **Classify the Reaction**:
- Since \( \text{HgI}_2 \) is initially a precipitate and it dissolves to form a soluble complex \( \text{K}_2[\text{HgI}_4] \), this reaction can be classified as a **precipitate dissolution reaction**.

5. **Select the Correct Option**:
- Based on the analysis, the correct answer is that this is a precipitate dissolution reaction.

### Final Answer:
The reaction \( \text{HgI}_2 + 2\text{HI} \rightarrow \text{K}_2[\text{HgI}_4] \) is classified as a **precipitate dissolution reaction**.

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