280mls of what? Like Borek: said this makes a difference. Ok, zo you're reading a label of HCl, so they measured out 280mls of HCl, a gas, and stirred it into some water? It's silly to assume that would work like I just described. Now, if you bubble HCl into water, until the water can take no more, that's approx 35%, and that what industry tends to work with.