I teach an introductory inorganic course at the first year level.  One of the key skills I want them to master in those first weeks of lab is the idea of turning a chemical description into equations (plus at the same time learning basic lab technique like filtering and observing).  I have used both the copper cycle lab and an alum synthesis lab for this purpose in the past but I am getting a bit tired of those and looking for something new.

Does anyone have any experience generating small quantitites of anhydrous HBr? NaBr and ortho-phosphoric acid did not seem to work overly well. At least I don't seem to be generating much of the gas. I have used NaCl and H2SO4 to generate HCl in the past and that is a very rapid and vigorous reaction.