Year 11 Chemists explore Acid/Base Chemistry

During week 2 of Term 3, Uni High’s Year 11 Chemistry classes ran experiments to explore the precision and accuracy of a variety of acid/base indicators, comparing their results with a digital pH meter.  The students discovered that pouring boiling water over red cabbage creates a great indicator, with the cabbage juice then showing a range of different colours when placed in solutions of differing pHs.  Acids turn the cabbage water red, while alkaline solutions turn it blue. Neutral solutions show a yellow/green colour.  A similar pattern was found with Universal Indicator, while an indicator such as Bromothymol Blue will only show two colours, yellow and blue.  Students also learnt how to calculate the concentration of H3O+ (acid) ions and OH- (base) ions present in a solution, by using the pH given when analysed with a digital pH meter.