Select the correct statement.

Options

A. Ostwald's method of preparation of `HNO_(3)` is based upon catalytic oxidation of `NH_(3)` by atmospheric oxygen.
B. `HNO_(2)` acts as both oxidising and reducing agents.
C. `NO_(2)` reacts with `O_(3)` to form `N_(2)O_(5)`
D. All of these

Explanation

To solve the question, we need to evaluate each of the given statements about the P-block elements and their reactions. Let's analyze each statement step by step.

### Step 1: Analyze the First Statement
**Statement 1:** The Ostwald method of preparation of HNO3 is based upon catalytic oxidation of ammonia by atmospheric oxygen.

**Analysis:**
- The Ostwald process involves the oxidation of ammonia (NH3) to produce nitric acid (HNO3).
- This reaction typically occurs in the presence of a catalyst, such as platinum or rhodium, at high temperatures (around 850°C) and pressures (about 5 atmospheres).
- The ammonia is oxidized using atmospheric oxygen to produce nitric oxide (NO), which is further oxidized to nitrogen dioxide (NO2) and then converted to nitric acid.

**Conclusion:** This statement is **correct**.

### Step 2: Analyze the Second Statement
**Statement 2:** HNO2 acts as both an oxidizing and reducing agent.

**Analysis:**
- HNO2 (nitrous acid) can indeed act as both an oxidizing agent and a reducing agent.
- As an oxidizing agent, it can convert ferrous ions (Fe²⁺) to ferric ions (Fe³⁺) and iodide ions (I⁻) to iodine (I2).
- As a reducing agent, it can be oxidized to nitrate ions (NO3⁻) by strong oxidizing agents like KMnO4 or chlorine.

**Conclusion:** This statement is **correct**.

### Step 3: Analyze the Third Statement
**Statement 3:** NO2 reacts with ozone to form N2O5.

**Analysis:**
- When nitrogen dioxide (NO2) reacts with ozone (O3), it can indeed form dinitrogen pentoxide (N2O5) along with the release of oxygen (O2).
- The reaction can be represented as:
\[ 2 NO2 + O3 \rightarrow N2O5 + O2 \]

**Conclusion:** This statement is **correct**.

### Step 4: Evaluate the Final Statement
**Statement 4:** All of the above statements are correct.

**Conclusion:** Since all three previous statements have been confirmed as correct, this statement is also **correct**.

### Final Answer
The correct answer is **D: All of the above statements are correct.**

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