Experiment 2.
In this case an excess of sulphuric acid was used. After the oxalic acid had all been decomposed or driven off the mass turned black and became very pitchy. Nothing could be done with it so it was thrown away.
In this case an excess of sulphuric acid was used. After the oxalic acid had all been decomposed or driven off the mass turned black and became very pitchy. Nothing could be done with it so it was thrown away.