Hcl

• Chlorine


  Bleaches vegetable or organic matter in the presence of moisture
• Bleaching effect of chlorine is permanent
• Preparation of hydrochloric acid

  1. Heat sodium chloride with concentrated sulphuric acid

  2. NaCl + H2SO4 → NaHSO4 + HCl

  3. NaHSO4 + NaCl → Na2SO4 + HCl
• Drying of HCl gas

  Pass through concentrated sulphuric acid
• Hydrochloric acid


  • Colourless and pungent smelling gas
  • Easily liquefied to a colourless liquid (b.p.189 K)
  • Freezes to a white crystalline solid (f.p. 159 K)
  • Extremely soluble in water and ionises
• Aqueous solution of HCl

  • Called hydrochloric acid
  • High value of dissociation constant (Ka) indicates it is a strong acid in water
• Reaction of HCl with NH3

  Gives white fumes of NH4Cl
• Formation of aqua regia

  1. Mix 3 parts concentrated HCl and 1 part concentrated HNO3

  2. Used for dissolving noble metals, e.g., gold, platinum
• Decomposition of salts by HCl

  Carbonates, hydrogencarbonates, sulphites, etc.
• When HCl reacts with finely powdered iron

  It forms ferrous chloride and not ferric chloride