Group 15: Nitrogen Acid
* In the laboratory, HNO3 is prepared by heating NaNO3 with concentrated H2SO4.
On a commercial scale, HNO3 is prepared by Ostwald’s process. The steps are:
* Catalytic oxidation of NH3 into NO
* Oxidation of NO to NO2
* Formation of HNO3 from NO2
* An aqueous solution HNO3 undergoes ionisation to produce H3O+ and NO–3.
* Hot and concentrated HNO3 reacts with “Cu” and “Zn” to give NO2.
* Dilute HNO3 reacts with “Cu” to give NO, and with “Zn” to give N2O.
* Noble metals dissolve in aqua regia, of which HNO3 is a constituents.
* Concentrated HNO3 oxidises non- metals to their corresponding higher oxoacids.
* The brown ring test confirms the presence of nitrate ions in a given salts.
