]]>
LearnNext
Get a free home demo of LearnNext

Available for CBSE, ICSE and State Board syllabus.
Call our LearnNext Expert on 1800 419 1234 (tollfree)
OR submit details below for a call back

clear

Group 15: Nitrogen - Oxides

5,983 Views
Have a doubt? Clear it now.
live_help Have a doubt, Ask our Expert Ask Now
format_list_bulleted Take this Lesson Test Start Test

Group 15: Nitrogen - Oxides - Lesson Summary

Nitrogen forms a number of oxides that exhibit a wide range of oxidation states.

Oxides of nitrogen:                                              Oxides of Nitrogen                         Name       Formula    Oxidation State
       of Nitrogen
Nitrogen (I) oxide / Nitrous oxide  N 2O       +1 Nitrogen (II) oxide / Nitric oxide  NO       +2 Nitrogen (III) oxide / Dinitrogen trioxide  N 2O 3       +3 Nitrogen (IV) oxide / Nitrogen dioxide /
Dinitrogen tetroxide  NO 2/N 2O 4       +4 Nitrogen (V) oxide / Dinitrogen pentoxide  N 2O 5       +5
 
Nitrous oxide or dinitrogen oxide (N2O):
Nitrous oxide is called laughing gas. It is usually prepared by heating ammonium nitrate gently to 240 0c. It is a colourless gas that is fairly soluble in cold water and the least soluble in hot water.
Nitrous oxide is a neutral oxide.

Structure:
Nitrous oxide is a linear molecule that is a resonance hybrid of the two forms.

 

The bond lengths in the molecule are 113 pm and 119 pm.

Nitrogen monoxide or nitric oxide (NO):
It is prepared by the reduction of nitrite salt with ferrous sulphate.

2NaNO2 + 2FeSO4 + 3H2SO4     → Fe2(SO4)3 + 2NaHSO4 + 2H2O + 2NO
Sodium    Ferrous     Sulphuric         Ferric          Sodium      Water    Nitric
nitrite       Sulphate     acid            sulphate        hydrogen                  oxide
                                                                                    sulphate

Nitric oxide is a colourless gas that attains blue colour when liquefied. It is sparingly soluble in water. It is also a neutral oxide.

Structure:
It is a linear molecule. It is a resonance hybrid of the two forms. The bond length is 115 pm which is intermediate between double bond and triple bond.

 

It is paramagnetic in nature.

Dinitrogen trioxide or nitrogen sesquioxide (N2O3):
It is obtained as a blue liquid when a mixture of nitric oxide and nitrogen dioxide or dinitrogen tetra oxide is cooled to below minus 200c.

                                                                 Cooling
2NO           +          N2O4                           →                  2N2O3
Nitric oxide    Dinitrogen tetroxide        Below -20°C      Dinitrogen trioxide

It is an anhydride of nitrous acid.
It is an acidic oxide.

Structure:
It is a planar molecule.
It is a resonance hybrid of these two forms.
 
               
 
Nitrogen dioxide (NO2):
It is prepared by heating lead nitrate at about 673 K.

                      Heat
2Pb(NO3)2      →              4NO2          +          2PbO     +     O2
lead nitrate   637K    Nitrogen dioxide       lead(II) oxide    Oxygen

Nitrogen dioxide is a brown gas that is a mixed anhydride of nitrous acid and nitric acid. It is an acidic oxide.

Structure:
The molecule is angular in shape with a bond angle of 134 degrees and bond length of 120 pm.

       

The molecule exists as a resonance hybrid. It is a paramagnetic substance.
Due to the presence of unpaired electron it dimerise to a colourless dinitrogen tetroxide molecule that has an even number of electrons. At low temperatures, nitrogen dioxide associates to solid dinitrogen tetroxide.

Dinitrogen pentoxide (N2O5):
It is prepared by the dehydration of nitric acid with phosphorus pentoxide.

                                                      Dehydration
4HNO3        +   P4O10                           →              4HPO3                     +          2N2O5
lead nitrate       Phosphorus pentoxide              Metaphosphoric acid              Dinitrogen pentoxide 

It is a colourless crystalline deliquescent solid. Readily dissolves in water to give nitric acid.
It is an anhydride of nitric acid. It is an acidic oxide.

Structure:
It is a planar molecule.
The molecule exists as a resonance hybrid.

          

Planar structure is observed only in its vapour state, it is ionic in the solid state. The ionic solid is referred to as nitronium nitrate.                

Comments(0)

Feel the LearnNext Experience on App

Download app, watch sample animated video lessons and get a free trial.

Desktop Download Now
Tablet
Mobile
Try LearnNext at home

Get a free home demo. Book an appointment now!

GET DEMO AT HOME