Acids and bases

2.6.2 Making salts

Acids and bases

  1. Bases are metal oxides & hydroxides
  2. Alkalis are soluble bases
  3. Ammonia dissolves in water to form an alkaline solution, and produces ammonium salts that are important as fertilisers
  4. pH

    1. The pH scale is a measure of the acidity or alkalinity of a solution
    2. It is a logarithmic scale with pH 7 denoting a neutral solution and with most solutions having a pH between 0 & 14
    3. The Arrhenius theory states that acids dissociate when dissolved in water and increase the concentration of Hydrogen ions, H+(aq), in solution, whilst alkalis increase the concentration of Hydroxide ions, OH-(aq)1
    4. Universal indicator is a solution of several compounds that exhibits several smooth colour changes over the pH scale that correlates with the visible spectrum, with green denoting pH 7

  1. The more accepted Brønsted-Lowry theory states that in an acid-base equation, the acid donate a Hydrogen ion to form its conjugate base, whilst the base accepts a Hydrogen ion to form its conjugate acid