`NH_(3)+O_(2) underset(Delta)overset(Pt) to A+H_(2)O`
`A+O_(2) to B`,
`B+O_(2)+H_(2)OtoC`
A, B and C are:

Options

A. `N_(2)O,NO_(2) and HNO_(3)`
B. `NO,NO_(2) and HNO_(3)`
C. `NO_(2),NO and HNO_(3)`
D. `N_(2)O,NO and HNO_(3)`

Answer

To solve the problem step by step, we will analyze the given reactions and identify the compounds A, B, and C.

### Step 1: Identify Compound A
The first reaction is:
\[ \text{NH}_3 + \text{O}_2 \xrightarrow{\Delta, \text{Pt}} A + \text{H}_2\text{O} \]

When ammonia (NH₃) reacts with oxygen (O₂) in the presence of a platinum catalyst and heat, it produces nitrogen monoxide (NO) and water (H₂O). Therefore, we can identify:
\[ A = \text{NO} \]

### Step 2: Identify Compound B
The second reaction is:
\[ A + \text{O}_2 \rightarrow B \]

Substituting A with NO, we have:
\[ \text{NO} + \text{O}_2 \rightarrow B \]

Nitrogen monoxide (NO) reacts with oxygen (O₂) to form nitrogen dioxide (NO₂). Thus, we can identify:
\[ B = \text{NO}_2 \]

### Step 3: Identify Compound C
The third reaction is:
\[ B + \text{O}_2 + \text{H}_2\text{O} \rightarrow C \]

Substituting B with NO₂, we have:
\[ \text{NO}_2 + \text{O}_2 + \text{H}_2\text{O} \rightarrow C \]

Nitrogen dioxide (NO₂) reacts with oxygen (O₂) and water (H₂O) to produce nitric acid (HNO₃). Therefore, we can identify:
\[ C = \text{HNO}_3 \]

### Summary of Compounds
- A = NO (Nitrogen monoxide)
- B = NO₂ (Nitrogen dioxide)
- C = HNO₃ (Nitric acid)

### Final Answer
Thus, the compounds A, B, and C are:
- A = NO
- B = NO₂
- C = HNO₃