Thermometric Titration of Orange Juice Acidity
Jonathan Shim
David Thompson
Floor Location : J 121 D

This project tests to see how the acidity level of orange juice changes over time in different temperature environments and if the thermometric titration is a reliable way of titrating. Thermometric titrations can be a good way to titrate as it relies on heat given off by a reaction to determine an endpoint. As all reactions are either exothermic, giving off heat energy, or endothermic, taking in heat energy, it is possible to test the acidity change of orange juice using this method by looking for inflection points on temperature vs. volume graphs. Titrations using acid-base indicators such as phenolphthalein are commonly used but because orange juice is coloured, it may be more difficult to determine the endpoint via colour changes. Thermometric titrations avoid this problem by looking for temperature changes and not colour changes. Comparative testing determined that the thermometric and color indicator titrations are relatively similar, within error margins. Because of this, thermometric titration is considered a reliable method, and equally or more accurate than a color indicator titration. It was also observed that the there was a pattern in how acidity of the orange juice increases over time; that the acidity level changes the most within the first three days, after which it increases less. Finally, it was also observed that storing orange juice in a refrigerated environment resulted in a slower and less of an increase in acidity than if the orange juice was stored at room temperature.