You have the following substances: \(NH_3\), \(O_2\), \(Pt\) and \(H_2O\). Arrange the following equations for the preparation of \(N_2O\) from these compounds.
A. \(NH_4NO_3 (aq) \underset{\text{at room temperature}}{\overset{\text{vacuum evaporation}}{\longrightarrow}}NH_4NO_3 \overset{523 K}{\longrightarrow}N_2O (g) + 2H_2O\)
B. \(NH_3 (g) + HNO_3 (aq) \longrightarrow NH_4NO_3 (aq)\)
C. \(3NO_2 (g) + H_2O (l) \longrightarrow 2HNO_3 (aq) + NO(g)\)
D. \(2NO (g) + O_2 (g) \longrightarrow 2NO_2 (g)\)
E. \(4NH_3 (g) + 5O_2 (g) \underset{1100 K}{\overset{Pt}{\longrightarrow}} 4NO (g) + 6H_2O (g)\)
Choose the correct answers from the options given below:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → E, D, C, B, A
\( \ce{N2O} \) is made by heating ammonium nitrate. With only \( \ce{NH3} \), \( \ce{O2} \), Pt and \( \ce{H2O} \) available, the \( \ce{NH4NO3} \) has to be made first, so nitric acid is prepared from ammonia by Ostwald’s process and then neutralised with more ammonia:
E — catalytic oxidation of ammonia over Pt: \( \ce{4NH3} \) + \( \ce{5O2} \) → 4NO + \( \ce{6H2O} \).
D — nitric oxide combines with oxygen: 2NO + \( \ce{O2} \) → \( \ce{2NO2} \).
C — \( \ce{NO2} \) dissolves in water to give nitric acid: \( \ce{3NO2} \) + \( \ce{H2O} \) → \( \ce{2HNO3} \) + NO.
B — nitric acid is neutralised by ammonia: \( \ce{NH3} \) + \( \ce{HNO3} \) → \( \ce{NH4NO3} \).
A — the solid ammonium nitrate is heated: \( \ce{NH4NO3} \) → \( \ce{N2O} \) + \( \ce{2H2O} \).
Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.