On one occasion during junior year, I was listening to my chemistry teacher attentively when he spoke of cuprous sulfate. For those who are unacquainted with terminology, this would have been the old name (the name I still use) for copper(I) sulfate. I informed Mr. D’Alesandro that the only existing copper sulfate was cupric sulfate, CuSO₄, not cuprous sulfate, Cu₂SO₄. Cuprous sulfate didn’t exist.
Was I correct? Mr. D’Alesandro told me he’d tell me more in class the next day.
Cuprous Sulfate: My ComeuppanceAnd he did. Although one can make cupric sulfate pentahydrate by the simple combination of copper, sulfuric acid, and water,
Cu + H₂SO₄ + 5 H₂O → CuSO₄•5H₂O + H₂↑the reaction he wrote on the blackboard was,
Cu₂O + (CH₃)₂SO₄ → (CH₃)₂O + Cu₂SO₄This reaction reads: cuprous oxide plus dimethylsulfate yields dimethylether plus cuprous sulfate. I’d been wrong. And what was worse, I had questioned his knowledge as an instructor although that was not my intent nor did he accuse me of it. I felt pretty foolish. I acknowledged what he said. We never discussed the matter again.
But just how wrong was I?
Acids, Bases, and SaltsFirst, this was an introductory chemistry course. The chemistry knowledge I had was all gained by my own effort. Then, too, cuprous sulfate is a most unusual compound of limited use. Although it can be stored in an anhydrous condition, it is not stable in the presence of moisture or of heat. You are quite unlikely to find it on any laboratory shelf.
Regretting the OutcomeSadly, my instructor was informed he would not be given tenure. When I found this out, I felt guilty, thinking somehow I may have contributed to his departure. I’ve often wondered what ever became of this fellow. Likely he went to a less demanding school. But I still do not know. Maybe I never will.