`HgS darr+HNO_(3)("conc.") to `No dissolution.

Options

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

Answer

To analyze the reaction between mercury(II) sulfide (HgS) and concentrated nitric acid (HNO₃) where it is stated that there is "no dissolution," we can break down the steps as follows:

### Step-by-Step Solution:

1. **Identify the Reactants**:
- The reactants in this reaction are mercury(II) sulfide (HgS) and concentrated nitric acid (HNO₃).

2. **Understand the Nature of HgS**:
- Mercury(II) sulfide (HgS) is a solid precipitate. It is insoluble in water and many acids, which is crucial to understanding the reaction.

3. **Consider the Reaction with HNO₃**:
- Concentrated nitric acid is a strong oxidizing agent and typically reacts with metals and some sulfides. However, in this case, we are told there is "no dissolution."

4. **Analyze the Meaning of "No Dissolution"**:
- The term "no dissolution" indicates that HgS does not dissolve in concentrated nitric acid. This suggests that the reaction does not proceed to form soluble products.

5. **Determine the Type of Reaction**:
- Given that there is no change in the state of the reactants (HgS remains solid), and no products are formed, we conclude that this is a case of "no reaction."

6. **Conclusion**:
- Since there is no observable change or formation of products, the best description of this reaction is that it results in "no reaction."

### Final Answer:
- The answer to the question is **"no reaction."**