Titration

• What is the aim of the investigation described in the study material?

  To find the concentration of a dilute sulfuric acid solution using sodium hydroxide.
• What is the balanced chemical equation for the reaction between sulfuric acid and sodium hydroxide?

  H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O
• What equipment is needed for the titration experiment?

  • 25 cm³ volumetric pipette
  • Pipette filler
  • 50 cm³ burette
  • 250 cm³ conical flask
  • Small funnel
  • White tile
  • Clamp stand and clamp
  • 0.1 M sodium hydroxide solution
  • Sulfuric acid
  • Phenolphthalein indicator
• How much sodium hydroxide should be measured into the conical flask?

  25 cm³
• Why is the conical flask placed on a white tile during the titration?

  To better observe the color change of the solution.
• What should be done after filling the burette with sulfuric acid?

  Record the initial reading of acid in the burette.
• How should readings from the burette be taken?

  From the bottom of the meniscus.
• How many drops of phenolphthalein indicator should be added to the conical flask?

  5 drops
• What happens to the color of the solution during the titration?

  The solution changes from pink to colorless.
• What should be done when the color change occurs in phenolphthalein?

  Close the burette and record the final reading.
• What is the titre in the context of this experiment?

  The volume of acid used to neutralize the alkali.
• How many times should the titration be repeated?

  Until consistent results are obtained.
• What is the acceptable range for consistent results in this titration?

  Within ± 0.1 cm³ of each other.
• How should the results of the titration be presented?

  • Present results in a table.
  • Calculate the mean titre, discarding any anomalies.
• How do you calculate the number of moles of sodium hydroxide used in the titration?

  By using the volume and concentration of sodium hydroxide.
• What is the ratio of sodium hydroxide to sulfuric acid in the balanced equation?


  1. 1
• What formula is used to calculate the concentration of sulfuric acid?

  Concentration = (moles × volume) / mean volume
• What is the purpose of using phenolphthalein in the titration?

  • It acts as an acid-base indicator.
  • It changes color at the endpoint of the titration.