The mixture of concentrated `HCl` and `HNO_(3)` made in `3:1` ratio contains

Options

A. `ClO_3`
B. `NOCl`
C. `NCl_3`
D. `N_2O_4`

Explanation

To solve the question regarding the mixture of concentrated HCl and HNO3 in a 3:1 ratio, we need to analyze the components formed when these two acids react.

### Step-by-Step Solution:

1. **Identify the Mixture**:
The mixture consists of concentrated hydrochloric acid (HCl) and concentrated nitric acid (HNO3) in a 3:1 ratio. This means for every 3 parts of HCl, there is 1 part of HNO3.

2. **Recognize the Mixture Name**:
This specific mixture of HCl and HNO3 is known as **aqua regia**. Aqua regia is known for its ability to dissolve noble metals such as gold and platinum.

3. **Understand the Reaction**:
When HCl and HNO3 are mixed, they undergo a chemical reaction. The primary products of this reaction can include nitrosyl chloride (NOCl), chlorine gas (Cl2), and water (H2O).

4. **Write the Reaction Equation**:
The reaction can be represented as follows:
\[ \text{HNO}_3 + 3 \text{HCl} \rightarrow \text{NOCl} + \text{Cl}_2 + 2 \text{H}_2\text{O} \]
This indicates that the products formed include nitrosyl chloride (NOCl) and chlorine gas (Cl2).

5. **Analyze the Options**:
The question provides several compounds: ClO3, NOCl, NCl3, N2O4. From our reaction, we can see that:
- ClO3 (chlorate) is not formed.
- NOCl (nitrosyl chloride) is formed.
- NCl3 (nitrogen trichloride) is not formed.
- N2O4 (dinitrogen tetroxide) is not formed.

6. **Conclusion**:
The only compound from the options that is present in the mixture is **NOCl**.

### Final Answer:
The mixture of concentrated HCl and HNO3 made in a 3:1 ratio contains **NOCl**.

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