Water can act as an acid or a base based on the Brønsted-Lowry acid theory. If it acts as a Bronsted-Lowry acid, the water molecule would donate a proton (H+), also written as a hydronium ion (H3O+). If it acts as a Bronsted-Lowry base, it would accept a proton (H+). An acid hydrolysis reaction is very much the same as an acid dissociation reaction.