C4.2.5 - Titrations (triple tier)

• The volumes of acid and alkali solutions that react with each other can be measured by titration using a suitable indicator.
• Describe how to carry out titrations using strong acids and strong alkalis only to find the reacting volumes accurately: Setting up the required practical

  The required apparatus is: burette, pipette and filler, conical flask and white tile

  The reagents are: an acid of unknown concentration, sodium hydroxide solution of known concentration, a suitable indicator, for example methyl orange or phenolphthalein

  Hazard: Dilute sodium hydroxide solution - Causes skin and serious eye irritation -> Wear gloves and eye protection, and use a pipette filler
• Describe how to carry out titrations using strong acids and strong alkalis only to find the reacting volumes accurately: Method

  • Using a pipette filler and pipette, add 25 cm3 to the bottom of the white beaker.
  • Add a few drops of indicator and place the Erlenmeyer flask on a white tile.
  • Fill the buret with acid and check the initial volume.
  • Slowly add the acid from the buret to the bottom of the Erlenmeyer flask and shake to mix.
  • Add acid throughout (the color of the first indicator will change).

  
• Calculate the chemical quantities in titrations involving concentrations in mol/dm3 and in g/dm3.

  Moles/Volume

  Mass/Volume