Nitric acid - HNO2

Nitric acid (HNO2, sometimes also HONO) is a weak acid that is only stable in solution. In the gas phase, it can act as an intermediate pollutant in atmospheric chemistry. It is formed when nitric oxide (NO) and nitrogen dioxide (NO2) react with water (H2O), but it is a two-way equilibrium reaction. It can also be oxidised to very potent nitric acid (HNO3), which should not be confused with nitric acidity. 


  • Molecular weight:

    47.01 g/mol

  • Gaseous phase:

    Approx. 1 kg/m3