in chemistry water is actually an acid and a base albeit weak ones water is both a weak acid and base because its ionization constant is this is how water can create something like the grand canyon via erosion we usually consider waster to be neutral however in terms of classifying water from a chemical analysis standpoint water has the properties of an acid and a base the following are various definitions of the acid base dichotomy arrhenius acid generates h in solution base generates oh in solution br nsted lowery acid anything that donates a h proton donor base anything that accepts a h proton acceptor lewis acid accepts an electron pair base donates an electron pair thc loadee