Acids, Bases and Salts

Acids, Bases and Salts

1. Acids

   • Substances that produces hydrogen ions when dissolved in water
   • Properties
     • Acid + metal --> salt + hydrogen
     • Acid + carbonate --> salt + carbon dioxide + water
     • Acid+ metal oxide --> salt + water
     • Acid + metal hydroxide --> salt + water
     • Turns blue litmus paper and universal indicator red
     • Sour
     • Corrosive when highly concentrated
     • Conducts electricity when in aqueous solutions

2. Bases

   • Properties
     • Alkali + acid --> salt + water
     • Alkali + metal salt --> metal hydroxide + salt
     • Alkali + ammonium salt --> salt + ammonia + water
     • Soapy
     • Bitter
     • Turns red litmus paper and universal indicator blue
     • Corrosive when highly concentrated
     • Conduct electricity when in aqueous state
   • Substance that produces salt and water when reacted with acid
   • Alkali (base that dissolves in water) produces hydroxide ions when in water

3. Oxides

   • Metals burn in air to form basic oxides and amphoteric oxides
     • Metal oxide + water --> metal hydroxide
     • Basic oxides
       • High melting and boiling points
       • Basic oxide + acid --> salt + water
     • Amphoteric oxides
       • Amphoteric oxide + acid --> salt + water
       • Amphoteric oxide + alkali --> salt + water
   • Non-metals burn in air to form acidic oxides and neutral oxides
     • Acidic oxides
       • Acidic oxide + water --> acid
       • Acidic oxide + alkali --> salt + water

4. Measuring pH

   • Below 7 - acidic and above 7 - basic
     • 1 to 14 - red to violet
   • Indicators
     • Methyl Orange
       • Red to yellow - 1 to 14
     • Bromothymol blue
       • Yellow to blue - 1 to 14
     • Phenolphthalein
       • Colourless to pink - 1 to 14

5. Salts

   • Soluble
     • All nitrates, most chlorides, most sulphates, SPA carbonates
       • Titration
         • SPA salts
         • Both reactants are soluble and one is an acid
       • Adding excess solid
         • Non SPA salts
         • One is soluble (acid) and one is insoluble
   • Insoluble
     • AgCl, PbCl2, PbSO4, BaSO4, CaSO4, most carbonates
       • Precipitation
         • Both reactants are soluble
         • To get XY, use X nitrate + Sodium Y