Definition of nitrous acid in US English:

nitrous acid


  • An unstable, weak acid, existing only in solution and in the gas phase, made by the action of acids on nitrites.

    Chemical formula: HNO₂

    • ‘Some substances are capable of acting either as reductants or as oxidants, e.g., hydrogen peroxide and nitrous acid.’
    • ‘There are various other types of equally forgotten Victorian batteries: some best forgotten as they gave off toxic nitrous acid fumes and could only be used in well-ventilated areas.’
    • ‘Nitrite ions also present a more acute toxicity toward the photosynthetic apparatus especially in their acid form, nitrous acid, which can diffuse freely across membranes.’
    • ‘Products must undergo rigorous tests, which examine chemical residue, veterinary residue, fish residue, heavy metal, hormone, nitrous acid, additives and microorganism.’
    • ‘Secondary amines react with nitrous acid to give nitroso compounds, pale yellow oils that are insoluble in water.’


nitrous acid

/ˈnītrəs ˈasəd/