Seneca
Sign up

Brønsted-Lowry Acids & Bases (A2 Only)

Chemistry: AQA A Level, topic 2.5.1

Brønsted-Lowry Acids and Bases

The chemists Brønsted and Lowry defined what an acid-base reaction is.

Brønsted-Lowry acids

Brønsted-Lowry acids

  • A Brønsted-Lowry acid is a proton donor. This means that it gives up H+ ions in solutions. Examples of Brønsted-Lowry acids are:
  • Hydrochloric acid.
  • Sulfuric acid.
  • Phosphoric acid.
Brønsted-Lowry bases

Brønsted-Lowry bases

  • A Brønsted-Lowry base is a proton acceptor. This means that it accepts H+ ions in solutions. Examples of Brønsted-Lowry bases are:
  • Sodium hydroxide.
  • Potassium hydroxide.
  • Ammonia.
Acid/base equilibria

Acid/base equilibria

  • Brønsted-Lowry acids need something to give protons to - you don’t get free H+ ions.
  • When you add HCl to water, the water molecules act like a base and accept protons from the HCl. The equation is:
  • HCl + H2O → H3O+ + Cl−
  • The H3O+ ion is called a ‘hydronium’ ion.

Test yourself on Brønsted-Lowry Acids & Bases (A2 Only)

  • When you add HCl to water, the water molecules act like a base and accept protons from the HCl. Finish the equation of this reaction
    HCl + H2O →

Practise this topic for free