RP9: pH changes

Cards (2)

  • when strong alkali is added to weak base the pH curve will be higher up on the graph
  • Determine Ka practically:
    1. Measure 25cm3 of acid into a conical flask using volumetric pipette
    2. Use pH probe to measure initial pH
    3. Add 1cm3 of NaOH from a burette swirl and record pH
    4. Repeat until in excess
    5. Plot graph of pH against volume of NaOH
    6. Use vertical section to find the volume for neutralisation
    7. Half neutralisation point is half volume for neutralisation
    8. Read off pH at half neutralisation point AND give equation