Question

Which of the following compound does not give dinitrogen on heating ?

• A. Ba(N₃)₂
• B. NH₄NO₂
• C. NH₄NO₃
• D. (NH₄)₂Cr₂O₇

Answer 1

The Correct Option is A

Identifying the Compound That Does Not Produce Dinitrogen on Heating

Let's analyze each compound: 

1. Option (A) \( \text{Ba(N}_3\text{)}_2 \): This compound contains azide ions (\( \text{N}_3^- \)). When heated, it decomposes to form barium metal and dinitrogen gas (\( \text{N}_2 \)):

\( \text{Ba(N}_3\text{)}_2 (s) \rightarrow \text{Ba} (s) + 3\text{N}_2 (g) \)

1. This **does** produce dinitrogen gas.
2. Option (B) \( \text{NH}_4\text{NO}_2 \): This compound decomposes upon heating to form water and dinitrogen gas (\( \text{N}_2 \)):

\( \text{NH}_4\text{NO}_2 (s) \rightarrow \text{N}_2 (g) + 2\text{H}_2\text{O} (g) \)

1. This **does** produce dinitrogen gas.
2. Option (C) \( \text{NH}_4\text{NO}_3 \): With careful heating, ammonium nitrate decomposes into dinitrogen monoxide (nitrous oxide) and water. **Importantly**, it does not produce dinitrogen under normal decomposition.

\( \text{NH}_4\text{NO}_3 (s) \rightarrow \text{N}_2\text{O} (g) + 2\text{H}_2\text{O} (g) \)

1. While under certain conditions, with more intense heating, other products may form, the *primary* decomposition product is not dinitrogen.
2. Option (D) \( (\text{NH}_4)_2 \text{Cr}_2\text{O}_7 \): This compound decomposes upon heating to form chromium(III) oxide, dinitrogen gas, and water:

\( (\text{NH}_4)_2 \text{Cr}_2\text{O}_7 (s) \rightarrow \text{Cr}_2\text{O}_3 (s) + \text{N}_2 (g) + 4\text{H}_2\text{O} (g) \)

1. This **does** produce dinitrogen gas.

Conclusion: The correct answer is (C) \( \text{NH}_4\text{NO}_3 \) because its primary decomposition reaction produces dinitrogen monoxide (\( \text{N}_2\text{O} \)), **not** dinitrogen (\( \text{N}_2 \)).