Acids and bases

• Conjugate Acid + Base

  Conjugate pair: 2 species which differ by one proton
• Conjugate pair


  1. Conjugate base

  2. Conjugate acid
• Salt


  The H in acid is replaced by a Metal
• Neutralisation


  Reaction between acid + base to form salt + water
• Medicine


  • Alkaselzer + HCI
• Agriculture


  • Calcium hydroxide + Acidic Soil
• Environment


  • Acid + limestone lake
• Bee sting


  • Baking soda
• Strong Conjugate Acid


  Weak acid
• Amphotheric


  Act as acid or base eg. H₂O
• Hydronium ions


  Exist in solution, not hydrogen ions
• Arrhenius definitions restricted to aqueous solutions (other solvents eg.methylbenzene)
• Not all acid base reactions need water
• Bronsted-Lowry acid


  • Strong acid- good proton donor
  • Weak acid- poor proton donor
• Bronsted-Lowry base


  • Strong base- good proton acceptor
  • Weak base- poor proton acceptor
• Alkali


  Base (soluble in H₂O)
• Ionise in solution


  Conduct electricity
• Arrhenius acid:

  •acid- a substance that dissociates in water to give H+ ions

  • strong acid: mostly dissociate

  • weak acid: slightly dissociate
• Arrhenius base:

  •base- substance that dissociates in water to give OH-

  •strong base: mostly dissociates

  •weak base: slightly dissociates
• Basicity of acids: number of replaceable hydrogens in an acid.