Chemistry T3

• Salt preparation


  The process of making salts based on the solubility of the salt

  
• Factors to consider when preparing salts


  • Solubility of the salt
  • Solubility of the starting materials
  • Hydration of the salt

  
• Methods of salt preparation

  1. Direct combination

  2. Precipitation

  3. Titration

  4. Acid + metal

  5. Acid + insoluble base

  6. Insoluble carbonate + acid

  
• Ionic precipitation


  Method to prepare insoluble salts
• Direct combination


  Method to prepare anhydrous binary salts
• Titration


  Method to prepare sodium, potassium or ammonium salts

  
• Acid + metal


  Method to prepare soluble salts (reactive metals)
• Acid + insoluble base


  Method to prepare soluble salts, except Na, K and NH4+ salts

  
• Insoluble carbonate + acid

  Method to prepare soluble salts, except Na, K and NH4+ salts
• General procedure for salt preparation

  1. Add excess solid metal, oxide or carbonate to acid

  2. Filter mixture to remove excess solid

  3. Evaporate solution until crystallisation begins

  4. Allow solution to cool and crystallise

  5. Wash and dry crystals

  
• Sodium chloride is used as table salt and to preserve meat and vegetables
• Sodium chloride is electrolysed to obtain sodium and chlorine in the industry
• Ammonium nitrate and ammonium sulphate are used as plant fertilisers
• Magnesium sulphate, commonly called Epsom salt, is used as a bath-salt