Acid-Base TheoriesLet’s start our discussion of acids and bases by defining some terms that are essential to the topics that follow. Arrhenius acids and bases are:acid—a substance that increases the concentration of protons (H+) in waterbase—a substance that increases the concentration of hydroxide ions in water (OH-) These definitions are limited to aqueous solutions. Br nsted and Lowry acids and bases as:acid—a substance that donates a proton to another substancebase—a substance that accepts a protonThese definitions can also apply to reactions that are not aqueous, so they are more accurate.Lewis acids and bases are:acid—a substance that accepts an electron pair base—a substance that donates an electron pair Here are some other terms that you’ll need to be familiar with:hydronium (H3O+)—H+ riding “piggyback” on a water molecule; water is polar, and the positive charge of the naked proton is greatly attracted to one of the negative electron pairs on adjacent oxygenmonoprotic—describes acids that can donate one H+diprotic—describes acids that can donate two H+ ionspolyprotic—describes acids that can donate more than one H+ ionamphiprotic—describes a substance that can act as either an acid or a base. This means it can either lose a proton or gain one. Water is amphiprotic: it can form either a hydroxide ion or a hydronium ion. Other examples of amphiprotic substances are , ,