Compare the composition of nitric and nitrous acids. In which of these acids is the nitrogen mass fraction higher?
November 14, 2020 | Education
| Given: HNO3 and HNO2. Find: ω1 (N) – ?, ω2 (N) -?
Decision.
1. Mass fraction of nitrogen in HNO3.
Mr (HNO3) = Ar (H) + Ar (N) + 3 • Ar (O) = 1 + 14 + 3 • 16 = 63
ω1 (N) = (Ar (N) / Mr (HNO3)) • 100% = (14:63) • 100% = 22.2%
2. Mass fraction of nitrogen in HNO2.
Mr (HNO2) = Ar (H) + Ar (N) + 2 • Ar (O) = 1 + 14 + 2 • 16 = 47
ω2 (N) = (Ar (N) / Mr (HNO2)) • 100% = (14:47) • 100% = 29.8%
Answer: HNO2 contains more nitrogen by mass than HNO3.
