Copper reacts with conc.`HNO_(3)` top form copper nitrate, water and gives brown fumes of nitrogen oxide and the name of the reaction is

Options

A. `NO_(2)`, combination reaction
B. NO, redox reaction
C. `NO_(2)`, redox reaction
D. `N_(2)O` combination reaction

Answer

To solve the question regarding the reaction of copper with concentrated nitric acid (HNO3), we can follow these steps:

### Step 1: Write the chemical equation for the reaction
When copper (Cu) reacts with concentrated nitric acid (HNO3), the products formed are copper nitrate (Cu(NO3)2), water (H2O), and nitrogen dioxide (NO2), which is the brown gas mentioned in the question.

The balanced chemical equation for the reaction is:
\[ \text{Cu} + 4 \text{HNO}_3 \rightarrow \text{Cu(NO}_3\text{)}_2 + 2 \text{H}_2\text{O} + 2 \text{NO}_2 \]

### Step 2: Identify the type of reaction
This reaction is classified as a **redox reaction**. In a redox reaction, oxidation and reduction occur simultaneously.

### Step 3: Determine oxidation states
- In the reaction, copper (Cu) starts with an oxidation state of 0 and ends up with an oxidation state of +2 in copper nitrate (Cu(NO3)2). This indicates that copper is oxidized.
- Nitrogen in nitric acid (HNO3) has an oxidation state of +5 and is reduced to +4 in nitrogen dioxide (NO2). This indicates that nitrogen is reduced.

### Step 4: Conclusion
Since both oxidation (of copper) and reduction (of nitrogen) are occurring in this reaction, we conclude that this is a redox reaction.

### Final Answer
The name of the reaction is **redox reaction**, and the nitrogen oxide produced is **NO2** (nitrogen dioxide).

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