Properties of Dinitrogen Chemistry Notes
Properties of Dinitrogen :
Physical and chemical properties of dinitrogen are as follows
Physical Properties :
- It is a colourless, tasteless, non-toxie and odourless gas.
- It has two isotopes 14N and 15N
- It is non poisonous gas but animals die in its atmosphere for want of oxygen.
- It is very slightly soluble in water (23.2 cm3 per litre of water at 273 K and 1 bar pressure)
- Its freezing point is 63.2 K and boiling point is 77.2 K
- According to molecular orbital theory dinitrogen behave as dimagnetic. Its molecular orbital configuration is as follows
- It can be adsorbed by activated charcoal.
- It does not help in combustion. Dinitrogen itself is non-combustible.
- It is slighly lighter than air and its vapour density is 14.
Chemical Properties :
→ Dinitrogen is chemically inert under ordinary condition of temperature and pressure due to very high bond dissociation enthalpy (946 kJ mol). But under drastic conditions dinitrogen can react.
→ It is neutral to litmus.
→ Combustion : It is neither combustible nor a supporter or combustion but many active metals keep on burning in an atmosphere of dinitrogen and form of their respective ionic nitrides.
→ Reaction with Non-metals At some drastic conditions nitrogen reacts with non-metals and form covalent nitrides. Some important reactions of nitrogen with non-metals are as follows
→ Reaction with hydrogen (Haber’s process): When a mixture of dinitrogen and dihydrogen is heated at 700K under a pressure of 200 atmosphere, in prescence of iron oxide as catalyst and molybdenum as promoter, ammonia is formed with release of some energy.
→ Reaction with oxygen : Dinitrogen only at very high temperature (about 2000 K) combines with oxygen and forms nitric oxide (NO).
→ Reaction with alumina in presence of coke : Aluminium nitride is formed.
→ Reaction with calcium cyanamide is formed.
→ Calcium cyanamide is used as fertilizer because it reacts with water and form ammonir.
CaCN2 + 3H2O → CaCO3 + 2NH3 (CaCN2 + C) is used as fertilizer under the trade name nitrolim.