Carrying out a Titration (triple only)

• What is a titration?


  A titration is a laboratory technique used to determine the volumes of acid and alkali solutions needed in a neutralisation reaction.
• Titration Practical

  1. Add a set volume of a strong alkali to a conical flask

  2. Add a few drops of a suitable indicator

  3. Place a strong acid of known concentration in a burette

  4. Take an initial reading of the volume of acid

  5. Gradually add the acid to the alkali, swirling regularly
• Titration Practical continued

  1. As soon as the indicator changes colour, stop adding acid

  2. Take a final reading of the volume of acid

  3. Subtract the final reading from the initial reading to calculate the volume of acid needed to neutralise the alkali
• Procedure for carrying out a titration


  1. Transfer 25 cm³ of sodium hydroxide solution into a conical flask

  2. Add 5 drops of indicator (e.g. methyl orange) to the alkali

  3. Place conical flask on a white tile

  4. Fill a burette with sulfuric acid

  5. Add acid to the alkali until the solution is neutral (colour change)

  6. Read the volume of acid added from the burette (at the bottom of the meniscus)

  7. Repeat the titration until two readings are within 0.1 cm³

  8. Take the mean of the two readings
• Titration


  A procedure to determine the concentration of an acid or alkali by neutralisation
• Neutralization reaction


  Reaction between an acid and an alkali to form a salt and water
• Pipette


  A laboratory instrument used to accurately measure and transfer small volumes of liquid
• Indicator


  A substance that changes colour at a specific pH, used to determine when neutralisation is complete
• Meniscus


  The curved upper surface of a liquid in a container, caused by the cohesion of the liquid molecules
• It is important to read the burette at the bottom of the meniscus
• Step 1 of the Titration practical:

  Transfer 25 cm cubed of sodium hydroxide solution into a conical flask
• Step 2 of the Titration practical:

  Add 5 drops of indicator (e.g. methyl orange) to the alkali - NaOH
• Step 3 of the Titration practical:

  Place conical flask on a white tile
• Step 4 of the Titration practical:

  Fill a burette with sulfuric acid
• Step 5 of the Titration practical:

  Take an initial reading of the volume of acid
• Step 6 of the Titration practical:

  Gradually add the acid to the alkali, swirling regularly.
• Step 7 of the Titration Practical:

  As soon as the indicator changes colour, stop adding acid.
• Step 8 of the Titration Practical:

  Take a final reading of the volume of acid added from the burette (at the bottom of the meniscus)
• Step 9 of the Titration Practical:

  Subtract the final reading from the inital reading to calculate the volume of acid needed to neutralize the alkali
• How many times should you repeat the titration?

  Until two readings are within 0.1 cm cubed.

  You should then take the mean of the two readings