Just Chemical Fun!
Just Chemical Fun!
Neutralisation with indicators making rainbows of colour
It’s not ALL hard work in Year 11 Chemistry – just most of the time! When exploring neutralization reactions, we found that sometimes it was a case of a colourless solution of acid reacting with a colourless solution of base, to form a colourless solution of some type of salt and water – not easy to observe! We then worked out that neutralization is always an exothermic reaction and so can be detected by its temperature increase; but even prettier was the following of the neutralization reaction using a single acid-base indicator, or a mixture of several. Universal indicator gave us some great colour changes, as we started with either excess acid or base and added its chemical opposite in careful proportions. Check out Bridget’s test tube (third from the left) in which she has managed to create a rainbow. She capitalised on the apparent lower density of the acid solution and carefully added it as an upper layer, deliberately restricting their mixing. They then began to diffuse into each other, react and create the graded rainbow you can see.
Ms Sandra Eustace
Chemistry Teacher