Chemistry > p Block Elements > 11.0 Oxyacids of Nitrogen
p Block Elements
1.0 Group $13$ – The Boron Family
2.0 Boron
3.0 Compounds of boron
4.0 Compounds of Aluminium
5.0 Group $14$ – The Carbon family
6.0 Allotropes of Carbon
7.0 Compounds of Carbon
8.0 Properties of Silicon
9.0 Group $15$-The Nitrogen Family
10.0 Oxides of nitrogen
10.1 Nitrogen Oxide $N_2O$ or Laughing gas (Neutral)
10.2 Nitric Oxide $NO$ (Neutral)
10.3 Nitrogen trioxide $N_2O_3$
10.4 Nitrogen dioxide or Di-nitrogen tetroxide $NO_2$ or $N_2O$
10.5 Nitrogen pentaoxide $N_2O_5$
11.0 Oxyacids of Nitrogen
11.1 Nitric acid $HNO_3$
11.2 Oxidation of Metalloid and Inorganic compounds by Nitric acid
11.3 Action of Metals & Proteins
12.0 Phosphorus
13.0 Oxygen
14.0 Sulphur
11.3 Action of Metals & Proteins
10.2 Nitric Oxide $NO$ (Neutral)
10.3 Nitrogen trioxide $N_2O_3$
10.4 Nitrogen dioxide or Di-nitrogen tetroxide $NO_2$ or $N_2O$
10.5 Nitrogen pentaoxide $N_2O_5$
11.2 Oxidation of Metalloid and Inorganic compounds by Nitric acid
11.3 Action of Metals & Proteins
Most of the metals will the exception of noble metals like gold and platinum are exactly by Nitric acid plays a double role in the action of metals i.e., it acts as an acid as well as an oxidising agent. Armstrong postulated that primary action of nitric acid is to produce hydrogen in the nascent form. Before this hydrogen is allowed to escape, it reduces the nitric acid into numbers of products like $NO_2,\ NO,\ N_2O,\ N_2$ or $NH_3$.
| Concentration of nitric acid | Metal | Main Product |
| Very dilute $HNO_3(6%)$ | $Mg,Mn$ | $H_2$ + Metal nitrate |
| $Fe,Zn,Sn$ | $NH_4NO_3$ + metal nitrate + $H_2O$ | |
| Dilute $HNO_3(20%)$ | $Pb.Cu,Ag,Hg$ | $NO$ + metal nitrate + $H_2O$ |
| $Fe,Zn$ | $N_2O$ + metal nitrate + $H_2O$ | |
| $Sn$ | $NH_4NO_3$ + $Sn{(N{O_3})_2}$ | |
| Concentrated $HNO_3(70%)$ | $Zn,Fe,Pb,Cu,Ag$ | $NO_2$ + metal nitrate + $H_2O$ |
| $Sn$ | $NO_2$ + ${H_2}Sn{O_3}$ Metastannic acid |
Action of Proteins
Nitric acid attacks forming a yellow nitro compound called xanthoprotein. It, therefore, stains skin and render wood yellow. This property is utilized for the test of proteins.
