05 Chemical Bonds
06 Acids, Bases and Salts
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6.1.3 The Role of Water in Acidic and Basic Properties

Role of Water to Show Properties of Acids

  1. The presence of water is essential for the formation of hydrogen ions and it is only the presence of these ions which causes acidity.
  2. Without water, an acid won’t show the properties of acid.

Without water, the molecules of ethanoic acid do not disassociate to form hydrogen ions. Without hydrogen ions, ethanoic acid does not shows acidity

With the presence of water, the molecules of ethanoic acid disassociate and form hydrogen ions. With the presence of  hydrogen ions, ethanoic acid shows acidity

The role of Water in Showing Alkaline Properties

  1. Alkali shows alkaline properties only in the presence of water.
  2. When water is present, ionisation of alkali produces OH, ions that are responsible for the alkali properties
  3. Without the presence of water, there are no free-moving hydroxide ions. Therefore, in the absence of, alkalis do not show alkalinity 
  4. Diagram below shows the illustration to investigate the role of water in showing alkaline properties of ammonia.
  5. The ammonia dissolve in water can turn red litmus paper to blue whereas the dry ammonia gas of the ammonia gas dissolve in propanone give no effect to the litmus paper.