Carrying out titrations

Sodium hydroxide against hydrochloric acid

1. Rinse the pipettes with deionised water and with the sodium hydroxide solution.

2. Using the 25.0cm³ pipette and safety pipette filler, place 25.0cm³ of sodium hydroxide solution into each of the three conical flasks.

3. Add 3 drops of phenolphthalein indicator to each conical flask.

4. Rinse the burette with deionised water and with the hydrochloric acid.

5. Fill the burette with hydrochloric acid.

6. Carry out a rough titration and two accurate titrations.

7. Use the table to record the results of your titrations. All values should be recorded to 1 decimal place.

Sodium carbonate against hydrochloric acid

1. Rinse and fill the burette with hydrochloric acid.

2. Rinse the pipette with sodium carbonate solution, using a pipette filler.

3. Transfer 25.0cm³ of sodium carbonate solution to a conical flask using the pipette and pipette filler.

4. Add 3-5 drops of methyl orange indicator to the solution in the conical flask. Place a white tile underneath the conical flask. Note the colour of the indicator in the flask.

5. Add the hydrochloric acid from the burette, with swirling, to the conical flask until the indicator changes from yellow to red . Record the reading on the burette.

6. Repeat the titration to achieve two concordant results and calculate the mean titre.