Which of the following will give `N_(2)` when heated?

Options

A. `NaN_(3)`
B. `NH_(4)NO_(2)`
C. `NH_(4)NO_(3)`
D. `(NH_(4))_(2)Cr_(2)O_(7)`

Answer

To determine which of the given compounds will produce nitrogen gas (N₂) when heated, we will analyze each option step by step.

### Step 1: Analyze Sodium Azide (NaN₃)
- **Reaction**: When sodium azide (NaN₃) is heated, it decomposes to form sodium metal and nitrogen gas.
- **Chemical Equation**:
\[ 2 \text{NaN}_3 \rightarrow 2 \text{Na} + 3 \text{N}_2 \]
- **Conclusion**: Sodium azide produces nitrogen gas upon heating.

### Step 2: Analyze Ammonium Nitrite (NH₄NO₂)
- **Reaction**: When ammonium nitrite is heated, it decomposes to form water and nitrogen gas.
- **Chemical Equation**:
\[ \text{NH}_4\text{NO}_2 \rightarrow 2 \text{H}_2\text{O} + \text{N}_2 \]
- **Conclusion**: Ammonium nitrite also produces nitrogen gas upon heating.

### Step 3: Analyze Ammonium Nitrate (NH₄NO₃)
- **Reaction**: When ammonium nitrate is heated, it decomposes to form nitrous oxide (N₂O) and water.
- **Chemical Equation**:
\[ \text{NH}_4\text{NO}_3 \rightarrow \text{N}_2\text{O} + 2 \text{H}_2\text{O} \]
- **Conclusion**: Ammonium nitrate does not produce nitrogen gas; instead, it produces nitrous oxide.

### Step 4: Analyze Ammonium Dichromate ((NH₄)₂Cr₂O₇)
- **Reaction**: When ammonium dichromate is heated, it decomposes to produce nitrogen gas, water, and chromium(III) oxide.
- **Chemical Equation**:
\[ (NH_4)_2Cr_2O_7 \rightarrow 2 \text{N}_2 + 4 \text{H}_2\text{O} + Cr_2O_3 \]
- **Conclusion**: Ammonium dichromate produces nitrogen gas upon heating.

### Final Conclusion
From the analysis:
- Sodium azide (NaN₃) produces nitrogen gas.
- Ammonium nitrite (NH₄NO₂) produces nitrogen gas.
- Ammonium nitrate (NH₄NO₃) does not produce nitrogen gas.
- Ammonium dichromate ((NH₄)₂Cr₂O₇) produces nitrogen gas.

Thus, the compounds that will give nitrogen gas when heated are:
1. Sodium azide (NaN₃)
2. Ammonium nitrite (NH₄NO₂)
3. Ammonium dichromate ((NH₄)₂Cr₂O₇)

### Answer:
The correct options are 1, 2, and 4.

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