yeah, so balloons full of sulfuric acid...I'm ~99% sure that would not work, leaving aside how exactly you plan to fill a balloon full enough it'd burst when thrown, tie it off, then throw it at someone without just popping it on yourself, where exactly are you planning to find balloons that wouldn't just melt from the acid? and if you dilute it enough to not melt the balloon, then you probably wont do more than irritate their skin, plus in order to not arouse suspicion you'd have to do it somewhere normal water balloons are in use, so it'd probably get splashed off by water pretty fast too