Addition of conc. `HNO_3` to conc. `H_2 SO_4` gives

Options

A. `SO_4^(2-)`
B. `SO_3`
C. `NO_3^(Ө)`
D. `NO_2^(oplus)`

Explanation

To solve the question regarding the addition of concentrated HNO3 (nitric acid) to concentrated H2SO4 (sulfuric acid), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reactants**:
We have concentrated nitric acid (HNO3) and concentrated sulfuric acid (H2SO4).

2. **Understand the Mixture**:
When concentrated HNO3 is mixed with concentrated H2SO4, it forms a mixture known as the "nitrating mixture." This mixture is often used in nitration reactions.

3. **Write the Reaction**:
The reaction between concentrated HNO3 and H2SO4 can be represented as:
\[ \text{HNO}_3 + \text{H}_2\text{SO}_4 \rightarrow \text{NO}_2^+ + \text{HSO}_4^- + \text{H}_2\text{O} \]
Here, the products formed include the nitronium ion (NO2+) and the bisulfate ion (HSO4-), along with water (H2O).

4. **Identify the Key Product**:
The key product of this reaction is the nitronium ion (NO2+), which is crucial for nitration processes, especially in organic chemistry.

5. **Conclusion**:
Thus, the addition of concentrated HNO3 to concentrated H2SO4 gives nitronium ions (NO2+) along with bisulfate ions and water.

### Final Answer:
The addition of concentrated HNO3 to concentrated H2SO4 gives nitronium ions (NO2+).