NEET Chemistry Notes p-Block Elements – Group-15 Elements -Dinitrogen

NEET Chemistry Notes p-Block Elements – Group-15 Elements -Dinitrogen

Dinitrogen

Dinitrogen

Uses

•  Liquid N₂ is used as refrigerant.
• It is used in the manufacture of HNO₃, NH₃, CACN₂ (calcium cyanamide) and other nitrogenous compounds.
•  It is used for filling electric bulbs.

Some Important Compounds of Nitrogen

Ammonia

• Ammonia is covalent. N,atom inNH₃ is sp³ hybridised. Due to the presence of lone pair of electrons, it acquires pyramidal shape.
• It is prepared by the following methods.
  
• Catalyst iron oxide with small amounts of K₂O and A1₂0₃ is used to increase the rate of attainment of equilibrium.
• NH₃is basic in nature, has tendency to form hydrogen bond, therefore soluble in water and form NH₄OH or NH₃(ag).
• Due to basic nature, NH₃ is a good complexing agent and reducing agent, e.g.
  
  
• NH₃ is used in refrigeration due to its large heat of evaporation and in manufacture of HNO₃, NaHC0₃, ammonium compounds and nitrogenous fertilizers.

Nitric Acid (HN03)

• It was earlier known as aqua fortis. It is prepared by the following processes.
  
•  Anhydrous HNO₃ is a colourless fuming pungent smelling liquid. It acquires yellow colour due to its decomposition.
  
• It has corrosive action on skin and causes painful sores.
•  It is very strong acid and form salts on reaction with basic oxides, carbonates, hydroxides etc.
  
• It acts as a strong oxidising agent.

Oxidising Properties of HN03

• Non-metals such as C, S, P and I₂ are oxidised to carbonic acid, §ulphuric acid, orthophosphoric acid and iodic acid respectively.
  
• NO is absorbed by FeS0₄ and a dark brown ring of nitroso ferrous sulphate is formed (ring test for nitrates).
  
• Metals like iron, cobalt, nickel, chromium, aluminium become passive in cone.
• HNO₃ due to the formation of a thin protective film of oxide on the surface of the metal.
•  HNO₃ is used in the manufacture of explosives such as TNT, picric acid, nitroglycerine, dynamite etc., fertilizers, such as NH₄NO₃, basic Ca(NO₃)2 etc., artificial silk, dyes, drugs.

Oxides of Nitrogen

The structures of oxides of nitrogen are given below

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