The Nitrous acid is a weak acid and available in solution as nitrate salts only. The chemical formula for the compound is HNO2 with a molecular weight 47.013 g/mol. The structure of the compound is given below.
This is a planar molecule with one nitrogen atom attached to two oxygen atoms with high electronegativity, one single bond, one double bond that could be resonant depends on the nature of solution. One oxygen atom is attached to the hydrogen atom strongly and holds it tightly and making a weak HNO2 acid ahead.
Because of presence of the double bind, nitrous acid may exist in the gas phase too and stable at the room temperature. It is naturally available in the atmosphere of earth and formed by mixing nitric oxide and water together. It further helps in regulating the ozone content available in the atmosphere. The acid is typically a pale blue solution with density of about 1 g/mL and only present as the solution in water or as nitrite salts.
It is a monobasic acid and releases only one proton at one time. Moreover, it can be defined as the weak acid that is not dissociated fully in water and remain in equilibrium with dissociated molecules. Similar to other acids, nitrous acid reacts with bases to form salts. It is quite unstable and decomposes quickly in solution.It is used in multiple forms by industries for the preparation of salts, amines, phenols etc. it is not toxic but there are chances of explosion when comes in contact with phosphorus trichloride (PCl3).