The products of the thermal decomposition of ammonium trioxonitrate(v) are?

Analysis

The question asks for the products formed when ammonium trioxonitrate(V)—commonly known as ammonium nitrate—undergoes thermal decomposition.

Concept

Thermal decomposition is the process where a single compound breaks down into two or more simpler substances when heated. Ammonium trioxonitrate(V) has the chemical formula $NH_4NO_3$.

When heated gently, it undergoes a specific decomposition reaction where the nitrogen atoms in the ammonium ion and the nitrate ion combine to form dinitrogen monoxide (also known as nitrous oxide or nitrogen(I) oxide) and water vapor.

Solution

The balanced chemical equation for the thermal decomposition of ammonium trioxonitrate(V) is:

1. Reactant: Ammonium trioxonitrate(V) ($NH_4NO_3$).
2. Products: • $N_2O$ is Nitrogen(I) oxide. • $2H_2O$ is Water (in the form of steam).

Comparing this to the provided options:

• Option A: Nitrogen (I) Oxide and Water — Matches our equation.
• Option B: Ammonia and Oxide — Incorrect.
• Option C: Nitrogen and Water — Incorrect (this would occur if the reaction were different).
• Option D: Nitrogen (IV) Oxide and Water — Incorrect (this is a common distractor).

Exam Tip

To avoid confusion in the exam hall, remember the "Ammonium Nitrate Rule":

• Gentle heating: Produces $N_2O$ (Nitrogen(I) oxide) and $H_2O$.
• Strong/Explosive heating: Produces $N_2$, $O_2$, and $H_2O$. Since the question implies standard thermal decomposition, always look for Nitrogen(I) oxide.