Oxides of Nitrogen 2
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| Discuss Oxides of Nitrogen 2 OXIDES OF NITROGEN
DINITROGEN TRIOXIDE
Dinitrogen trioxide is a very unstable substance and exists as such only in a solid form. In the liquid state it dissociates into NO and NO2.
PREPARATION
When a mixture of NO and NO2 is cooled, it freezes to give dinitrogen trioxide, which is a blue coloured solid.
NO + NO2 è N2O3
CHEMICAL PROPERTIES
- Acidic nature
- It is the anhydride of nitrous acid
N2O3 + 2KOH è 2KNO2 + H2O
NITROGEN DIOXIDE
It is a reddish brown gas and exists at room temperature. It is charecterised by the following
- Relative density 1.45
- Melting point -11.2OC
- Boiling point 21.2OC
PREPARATION
- By the action of heat on nitrates of heavy metals
- nitric acid when reduced with the help of metals like Cu yields nitrogen dioxide
2Pb(NO3)2 è 2PbO + 4NO2 + O2
4HNO3 + Cu è Cu(NO3)2 + 2H2O + 2NO2
CHEMICAL PROPERTIES
- On dissolving in water it gives a mixture of nitrous and nitric acids
- at low temperatures ( 10 - 15 OC) Nitrogen dioxide dimerises to form dinitrogen tetroxide .
2NO2 + H2O è HNO2 + HNO3
this is a reversible reaction.
-11OC
NO2 è N2O4
USES
- In the manufacture of nitric acid
- As a catalyst in the manufacture of Sulphuric acid in the lead chamber process
NITROGEN PENTOXIDE
It is a white crystalline solid and is also known as nitric anhydride. It melts at 30OC.
PREPARATION
It is prepared by dehydrating nitric acid
P2O5
2HNO3 è N2O5 + H2O
CHEMICAL PROPERTIES
- It decomposes when heated to more than 30OC
- On adding water it yields nitric acid (thus the term nitric anhydride)
N2O5 è 2N2O4 + O2
At 40OC it decomposes to yield NO2
2N2O5 è 4NO2 + O2
N2O5 + H2O è 2HNO3
OXYACIDS
|
NAME OF THE OXYACID |
FORMULA |
OXIDATION STATE OF NITROGEN |
|
Hyponitrous acid |
H2N2O2 ( emperically HNO) |
+1 |
|
Hydroxynitrous acid |
H4N2O4 ( emperically H2NO2) |
+2 |
|
Nitrous acid |
HONO or HNO2 |
+3 |
|
Pernitrous acid |
HOONO |
+4 |
|
Nitric acid |
HNO3 |
+5 |
|
Pernitric acid |
HNO4 |
+7 |
