What do you mean by "stronger"? Vodka will get you inebriated. Vinegar will probably just get you sick and ulcerate your stomach. In larger quantities.... 2 liters (about 2 quarts)of vodka would probably knock you out and possibly kill you depending on your size. A similar amount of vinegar would likely kill you. Or do you mean "stronger" taste? Depends on the type of vinegar and the brand of vodka. Theres some pretty terrible rotgut vodka out there and some sweet vinegars. Or do you mean in pH? With hydrochloric acid being 0 pH and water 7 ph - vinegar is acidic with a pH between 3 and 5. Vodka is basic - around 8 pH. The vodka would slightly neutralize your stomach acid and give you a bit of heartburn. The vinegar would exacerbate the acid in your stomach and would burn.