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 acidbase dichotomy  Arrhenius acid generates H in solution base generates OH in solution  BrnstedLowery 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