NITRIC ACID (HNO 3 )- The chemical formula of of nitric acid is HNO 3 . The original structure of nitric acid will be- HNO 3 is a molecule acid hence contains one-OH group attached directly with N-atom (Central atom), thus the structure of nitric acid molecule can be represented by the formula (HONO 2 ). Spectroscopic and electron diffraction studies have shown that HNO 3 molecule in the vapour state has trigonal planar structure with various bond angles and bond lengths. Both the structure is supported by the monobasic nature of HNO 3 . It may be seen from this structures that N-atom and all three O-atoms have an octet of electrons in their outer shell H-atom has two electrons in its shell. Preparation :- 1. In the laboratory, it is prepared by heating NaNO 3 or KNO 3 with conc. H 2 SO 4 . Raddish brown vapours of HNO 3 so produced are condensed in a water-coo