Titrations

• What is the purpose of titrations?


  To analyze the concentrations of solutions
• Why are titrations considered important?


  They are used to find out how much acid is needed to neutralize a quantity of alkali or vice versa
• What is used in the burette during a titration example provided?


  Acid
• What should be recorded after filling the burette?


  The initial reading of the burette
• What is the next step after recording the initial reading of the burette?


  Add a set volume of the unknown acid to the flask
• Why is it important to record the initial reading of the burette multiple times?


  To avoid wasting time looking up at every second
• What should you do when you think the end-point of the titration has been reached?


  Swirl the conical flask slightly more
• What indicates that the end-point of the titration has been reached?


  The indicator changes color
• What should be done after reaching the end-point?


  Record the final volume of acid in the burette
• How do you calculate the volume of acid used in the titration?


  By subtracting the initial reading from the final reading
• What is the purpose of performing a rough titration?


  • To increase the accuracy of the titration
  • To spot any anomalous results
• How many consistent readings are needed to get an end-point?


  Several consistent readings
• What should be done after obtaining several consistent readings?


  Repeat the whole titration a few times
• What is the acceptable range for consistent titration results?


  Within 0.10 cm³
• What should be done with anomalous results when calculating the mean?


  Ignore any anomalous results
• What are single indicators used for in titrations?


  • To estimate the pH of a solution
  • They show a variety of colors indicating different pH ranges
• What is a universal indicator made from?


  A mixture of different indicators
• How does the color of a universal indicator change?


  The color gradually changes from red
• What is the technique used to find an unknown concentration of an acid or alkali?

  Titration
• What equipment is used in a titration?

  • Pipette
  • Conical flask
  • Burette
  • White tile
• Why is a white tile used during titration?


  It helps to easily see when a color change takes place
• What is the first step in the titration practical?


  Use a pipette to add 25 cm³ of alkali to a clean conical flask
• What should be added to the conical flask after the alkali?


  Add a few drops of indicator
• What is the purpose of filling the burette with acid and noting the starting volume?


  To measure the amount of acid added during the titration
• What should you do while adding acid from the burette to the alkali in the conical flask?


  Swirl to mix
• When should you stop adding acid during the titration?

  When the endpoint is reached and the indicator changes color
• What should you note after reaching the endpoint in a titration?


  Final volume reading of the acid
• How do you calculate the total amount of acid added during titration?


  By subtracting the starting volume from the final volume reading
• What does it mean to get concordant results in titration?


  It means the volumes of acid are within 0-10 cm³ of each other
• What should you do with concordant results in titration?


  Use them to calculate the mean
• What are the three types of indicators used in titration?

  • Litmus: Acid = red, Alkali = blue
  • Phenolphthalein: Acid = colorless, Alkali = pink
  • Methyl orange: Acid = red, Alkali = yellow
• What happens when acid molecules are added to water?


  They ionise or dissociate
• What is the technique used to find an unknown concentration of an acid or alkali?

  Titration
• What equipment is used in a titration?

  • Pipette
  • Conical flask
  • Burette
  • White tile
• Why is a white tile used during titration?


  To easily see when the colour change takes place
• What is the first step in the titration practical?


  Use a pipette to add 25 cm³ of alkali to a clean conical flask
• What should be added to the alkali in the conical flask before starting the titration?


  A few drops of indicator
• What should you do after adding the acid from the burette to the alkali in the conical flask?


  Swirl to mix
• When should you stop adding acid during titration?

  When the endpoint is reached and the indicator changes colour
• What should you note after reaching the endpoint in a titration?


  The final volume reading