Acids, bases and salts

Acids, bases and salts

1. DEFINITIONS

   • Acid
     • Strong acids turn universal indicator paper red
   • Bases
     • React with acids to neutralise them to make a salt and water
     • They are usually metal oxides or metal hydroxides
     • Accepts hydrogen ions
   • Alkalis
     • Bases that dissolve in water
     • Strong alkalis turn universal indicator paper dark purple or blue
     • Contain hyrdoxide ions
   • Neutral solutions
     • Universal indicator paper: green

2. Nuetralisation reactions

   • Alkalis
     • Produce aqueous hyrdoxide ions, OH–(aq)
   • Acids
     • Produce aqueous hyrdrogen ions, H+ (aq)
   • When the H+(aq) ions from an acid react with the OH–(aq) ions from an alkali, a neutralisation reaction occurs to form water.
   • H+(aq) + OH–(aq) → H2O(l)

3. Salts

   • Hydrochloric acid → chloride
   • Sulphuric acid → sulphate
   • Nitric acid → nitrate
   • The first part of the name is 'ammonium' if the base used is ammonia.
   • Any metal from group 1 or 2 will give a white salts
   • Transition metals give a coloured salt
   • Souble salts
     • All nitrates, most sulfates, chlorides, bromides and iodides
   • Insouble salts
     • if you want to make an insoluble salt XY, mixing X nitrate with sodium Y will always work.

4. Ammonia

   • Is an alkali
   • If reacts with acids produces a salt instead of water
   • Many artificial fertilisers are ammonium salts, made by the reaction of an acid with ammonia solution.

5. Reactions with acids

   • MASH
     • Metal + Acid → Salt + Hyrdogen
   • AASH2O
     • Alkali + Acid → Salt + Water
   • BASHO