Strong and weak acids

• Types of acids


  • Strong acids
  • Weak acids
• Strong acids and weak acids are different, but which is better?
• Produce Protons in Water

  Acids ionise in aqueous solution to produce hydrogen ions
• Strong acids


  Completely ionise in water (e.g. hydrochloric and nitric acids)
• Weak acids


  Do not fully ionise in solution (e.g. acetic, citric and carbonic acids)
• Only a small proportion of weak acid particles dissociate to release hydrogen ions
• Concentration of H+ ions

  Determines the rate of reaction, so strong acids are more reactive than weak acids of the same concentration
• pH


  Measure of the concentration of hydrogen ions in a solution
• For every decrease of 1 on the pH scale, the concentration of H+ ions increases by a factor of 10
• The pH of a strong acid is always less than the pH of a weaker acid if they have the same concentration
• Acid strength (strong or weak) tells you what proportion of the acid molecules ionise in water
• Acid concentration


  Measures how much acid there is in a certain volume of water
• pH will decrease with increasing acid concentration regardless of whether it's a strong or weak acid
• You can have a dilute (not very concentrated) but strong acid, or a concentrated but weak acid