ZIMSEC O Level Combined Science Notes: Neutralisation/Salts

  • The acidity and alkalinity of a solution can be represented on the pH scale
  • If the pH is low i.e less than 7 then the solution is acidic
  • If the pH is high i.e higher than 7 then the solution is alkaline
  • If a solution has a pH of 7 then the solution is neutral
  • This means it is neither acidic or alkaline
  • The pH of an acid increases if a base is added to it
  • At some point if, we continue to add the base, the solution becomes neutral
  • When the base is added to the acid the acidity of of the solution decreases while its pH increases
  • When the mixture reaches a pH of 7  just enough of the base solution will have been added to the acid to neutralise the acid
  • Neutralisation is a reaction where an acid reacts with an alkali(base) to form a neutral solution of a salt and water.
  • When the acid is neutralised salt and water is formed
  • The word salt is used to refer to one of the by products formed when an acid and base react
  • Sodium chloride otherwise known as table salt or common salt is just one of the many types of salt
  • Other examples of salts are: copper sulphate, potassium permanganate, magnesium sulphate etc.
  • The word equation for neutralisation is:
  • \text{base+acid}\rightarrow\text{salt+water}
  • Not all bases are soluble in water as a result
  • Some metal oxides do not form alkaline solutions
  • Still these insoluble bases react with acids to form a solution of salt and water
  • Salt is always a byproduct of the neutralisation process

To access more topics go to the Combined Science Notes page,