`Hg(NO_(3))_(2)+NH_(3)("soln.")toMgO*HgNH_(2)NO_(3)darr`

Options

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

Answer

To solve the question regarding the reaction between Mercury(II) nitrate and ammonia solution, we will analyze the reaction step by step.

### Step-by-Step Solution:

1. **Identify the Reactants**:
The reactants in the reaction are Mercury(II) nitrate, represented as \( \text{Hg(NO}_3\text{)}_2 \), and ammonia solution, represented as \( \text{NH}_3 \text{(soln.)} \).

**Hint**: Always start by identifying the reactants in a chemical reaction.

2. **Write the Reaction**:
The reaction can be written as:
\[ \text{Hg(NO}_3\text{)}_2 + \text{NH}_3 \text{(soln.)} \rightarrow \text{MgO} \cdot \text{HgNH}_2\text{NO}_3 \]

**Hint**: Ensure you write the correct chemical formulas for the reactants and products.

3. **Analyze the Products**:
The product of the reaction is \( \text{MgO} \cdot \text{HgNH}_2\text{NO}_3 \). The presence of a downward arrow indicates that this product is a precipitate, meaning it is in solid form.

**Hint**: Look for indicators such as downward arrows to identify precipitates in a reaction.

4. **Determine the Type of Reaction**:
Since there is no precipitate on the reactant side (only solutions) and a precipitate is formed on the product side, this reaction is classified as a **precipitate formation reaction**.

**Hint**: Remember that a precipitate formation reaction occurs when a solid is formed from two solutions.

5. **Choose the Correct Option**:
Based on the analysis, the correct option is the one that states it is a precipitate formation reaction, as there was no precipitate on the reactant side and a precipitate was formed on the product side.

**Hint**: Compare your findings with the provided options to select the correct one.

### Conclusion:
The reaction \( \text{Hg(NO}_3\text{)}_2 + \text{NH}_3 \text{(soln.)} \rightarrow \text{MgO} \cdot \text{HgNH}_2\text{NO}_3 \) is a **precipitate formation reaction**.