2022 IB Diploma Extended Essays

orange colour (the solution with the indicator at the start of the titration was a bright yellow colour so, the yellow had a hint of blue when it reached its endpoint, making a muddy orange colour). Method 3: Back Titration Another retort stand was set up with another white tile and burette which was filled with 0.1M HCl. Method 3 also followed the same process as Method 2 (using bromothymol blue indicator), but the titration continued after reaching the endpoint (to have excess NaOH) which made the solution’s colour a dark blue/purple. Once the solution had excess NaOH, the solution was placed onto the second retort stand (with HCl) and another titration was performed till the solution’s colour reached the endpoint; a muddy orange- the colour will suddenly change from the blue colour to the muddy orange. The volume of HCl and NaOH before and after the titrations was noted. Method 4: Titration with pH Data Logger The apparatus was collected and set up as seen in diagram 1. The pH data logger was connected to a device before clamping it. The burette was filled to 0 with HCl through the funnel. 20ml of the wine was measured and transferred to the 50ml beaker using the 20ml pipette and bulb. The pH logger was set to start collecting and the beaker was raised to have the probe be submerged in the wine for a few seconds to collect the starting pH value. The titration started by keeping an eye on the pH and stopping to swirl the solution after every 2ml of HCl was used. Once the pH had reached a pH of 6, the titration was stopped after every 1ml. When the solution reached a pH of 7, the titration was stopped after every drop of HCl. The titration was completed once the solution had a pH of 8.2. The ending volume of HCl was noted and the experiment was repeated 5 more times to fulfil the 6 trials. 2.4 Risk Assessment Apparatus Risk Associated How it was managed Glass beaker and conical flask Any chips on the Before use, the beakers and conical flasks were carefully examined for any chips.

beaker/conical flask can cut the person handling them. Possibility of breakage or cuts on the glass

Volumetric pipette

The pipette was inspected and discard if there were any chipped parts