An update on the ‘mysterious white powder’ of my last post. It was the subject of some interest in the department today and we resolved to identify it.
Some crude analysis of the powder: it fizzes when you add it to a solution of HCl – almost certainly a carbonate of some sort.
The pH of the powder dissolved in water was done independently twice (I did it and then my lab mate did it not knowing I had already done it!) and we both got a pH of 11-12 – consistent (see this table) with either sodium carbonate or potassium carbonate (not bicarbonate, which would be more like a pH of 8-9).
I jokingly suggested that we should do a flame test on it next. Well, it turned out we have the capacity to do so and it was determined quite conclusively that it was in fact sodium carbonate. Debate rages on whether it is the anhydrous form or a decahydrate.