2022 IB Diploma Extended Essays

Diagram 1: Set up for Titration with pH sensor

Retort Clamps

50ml Burette

Deionised water bottle

pH sensor

50ml beaker

Titration tile

Retort Stand

2.3 Method Method 1: Titration using phenolphthalein

The apparatus was collected and set up as seen in diagram 1 (without the pH logger and beaker). The burette was filled to 0 with NaOH through a funnel. The wine was poured out of the bottle into one of the 100ml beakers to make access easier. The other 100ml beaker was used as the waste beaker. Using the 20ml pipette and bulb, 20ml of the wine was measured and transferred to one of the conical flasks. 5 drops of the phenolphthalein indicator was dropped into the wine and the flask was swirled to mix the indicator into the wine. After, the conical flask was placed on the retort stand with the white tile underneath it to clearly see the endpoint colour. The starting volume of NaOH in the burette was noted and the titration started. 1ml of NaOH was added to the wine until a hint of pink colour appeared. From this point onwards the solution was swirled after every few drops. Once the solution had reached an amber colour, the volume of NaOH in the burette was noted (because the solution is originally a pale-yellow colour, the pink from the indicator made the solution’s colour amber when it reached its endpoint). After rising out the conical flask in preparation for later trials, another 20ml of the wine was measured and transferred into another conical flask. The titration was performed again, taking note of the NaOH volume before and after the titration. This was repeated for another 4 times to make up the 6 trials. Method 2: Titration w/ bromo blue Method 2 followed the same process as Method 1 but used bromothymol blue indicator instead of phenolphthalein indicator. The titration was stopped after the solution reached a muddy