Which of the following on heating produces `NO_(2) ` ?

Options

A. `NaNO_(3)`
B. `AgNO_(3)`
C. `NH_(4)NO_(3)`
D. `NH_(4)NO_(2)`

Explanation

To determine which of the given compounds produces NO₂ upon heating, we will analyze each option step by step.

### Step 1: Analyze the first option - Sodium Nitrite (NaNO₂)

1. **Decomposition Reaction at 500°C:**
\[ 2 \, \text{NaNO}_2 \, \xrightarrow{500^\circ C} \, 2 \, \text{NO}_2 + \text{O}_2 \]
- At this temperature, sodium nitrite decomposes to produce nitrogen dioxide (NO₂) and oxygen (O₂).

2. **Decomposition Reaction at 800°C:**
\[ 4 \, \text{NaNO}_3 \, \xrightarrow{800^\circ C} \, 2 \, \text{Na}_2\text{O} + 2 \, \text{N}_2 + 5 \, \text{O}_2 \]
- At this higher temperature, sodium nitrite does not produce NO₂; instead, it yields sodium oxide (Na₂O) and nitrogen gas (N₂).

**Conclusion for NaNO₂:** It produces NO₂ at 500°C but not at 800°C.

### Step 2: Analyze the second option - Silver Nitrate (AgNO₃)

1. **Decomposition Reaction:**
\[ 2 \, \text{AgNO}_3 \, \xrightarrow{\text{heat}} \, 2 \, \text{Ag} + 2 \, \text{NO}_2 + \text{O}_2 \]
- Upon heating, silver nitrate decomposes to produce silver (Ag), nitrogen dioxide (NO₂), and oxygen (O₂).

**Conclusion for AgNO₃:** It produces NO₂ upon heating.

### Step 3: Analyze the third option - Ammonium Nitrate (NH₄NO₃)

1. **Decomposition Reaction:**
\[ \text{NH}_4\text{NO}_3 \, \xrightarrow{\text{heat}} \, \text{N}_2\text{O} + 2 \, \text{H}_2\text{O} \]
- Ammonium nitrate decomposes to produce nitrous oxide (N₂O) and water (H₂O).

**Conclusion for NH₄NO₃:** It does not produce NO₂.

### Step 4: Analyze the fourth option - Ammonium Nitrite (NH₄NO₂)

1. **Decomposition Reaction:**
\[ \text{NH}_4\text{NO}_2 \, \xrightarrow{\text{heat}} \, \text{N}_2 + 2 \, \text{H}_2\text{O} \]
- Ammonium nitrite decomposes to produce nitrogen gas (N₂) and water (H₂O).

**Conclusion for NH₄NO₂:** It does not produce NO₂.

### Final Conclusion:
The only compound that produces NO₂ upon heating is **Silver Nitrate (AgNO₃)**.

### Answer:
**The correct answer is option 2: AgNO₃.**

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