Ammonia

• Formula: NH3
• PHYSICAL PROPERTIES:

  1. Colourless
  2. Pungent gas
  3. soluble in water
  4. Denser than air
  5. Ammonia is a basic gas
• PREPARATION:

  Ammonia is made in the Haber process which involves a reversible reaction between nitrogen and hydrogen

  Nitrogen + Hydrogen ⇌ Ammonia

  2N2 + 3H2 ⇌ 2NH3

  CONDITIONS IN THE HABER PROCESS:

  • A temperature of 450°C
  • A pressure of 200 atmospheres
  • an iron catalyst (catalyst increases the rate of reaction but does not get used up)
• TEST FOR AMMONIA:

  1. Dip a glass rod in concentrated hydrochloric acid and place it in a sample of the gas
  2. A white smoke is observed

  Ammonia + Hydrochloric acid -> ammonium chloride

  NH3 + HCL -> NH4Cl

  NH3~ weak base NH4Cl~ white smoke
• USES FOR AMMONIA:

  Ammonia- Used in the manufacture of fertilisers as ammonia is a weak base, it reacts with acids to form ammonium salts

  EXAMPLES:

  Ammonia + sulfuric acid -> Ammonium sulfate

  2NH3 + H2SO4 -> (NH4)2SO4

  Ammonia + nitric acid -> ammonium nitrate

  NH3 + HNO3 -> NH4NO3

  The salts are very soluble in water, dissolve in soil to help plants absorb nutrients