JAMB Chemistry 1990 Question 31

Question 31

Nitrogen and its Compounds

The brown fumes given off when trioxonitrate (V) acid is heated consist of

  1. A.NO2 and O2
  2. B.H2O and NO2
  3. C.NO2, O2 and H2O
  4. D.NO, NO2 and H2O.
Show the answer and explanation

Answer: C (NO2, O2 and H2O)

Explanation

Heated nitric acid decomposes: 4HNO3 → 4NO2 + O2 + 2H2O. The brown colour is NO2, mixed with oxygen and steam.