In the catalytic oxidation of ammonia an oxide is formed which is used in the preparation of `HNO_(3)`. This oxide is

Options

A. `N_(2)O_(3)`
B. `N_(2)O_(4)`
C. `NO_(2)`
D. `NO`

Explanation

To solve the question regarding the oxide formed during the catalytic oxidation of ammonia that is used in the preparation of HNO3, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**: The catalytic oxidation of ammonia (NH3) primarily produces nitric oxide (NO) as one of the products. The reaction can be represented as:
\[ 4 NH_3 + 5 O_2 \rightarrow 4 NO + 6 H_2O \]

2. **Recognize the Product**: The oxide formed in this reaction is nitric oxide (NO). This is the key oxide that is used in the subsequent steps to prepare nitric acid (HNO3).

3. **Formation of Nitrogen Dioxide (NO2)**: The nitric oxide (NO) can further react with oxygen (O2) to form nitrogen dioxide (NO2):
\[ 2 NO + O_2 \rightarrow 2 NO_2 \]

4. **Preparation of Nitric Acid (HNO3)**: The nitrogen dioxide (NO2) can then react with water (H2O) to produce nitric acid (HNO3):
\[ 3 NO_2 + H_2O \rightarrow 2 HNO_3 + NO \]

5. **Conclusion**: Therefore, the oxide that is formed during the catalytic oxidation of ammonia and is used in the preparation of HNO3 is nitric oxide (NO).

### Final Answer:
The oxide formed in the catalytic oxidation of ammonia that is used in the preparation of HNO3 is **Nitric Oxide (NO)**.

---