Early in the history of chemistry it was noted that aqueousDescribing a solution in which the solvent is water. solutions of a number of substances behaved very similarly, although the substances themselves did not at first seem to be related. Solutions were classified as acids if they had the following characteristics: sour taste; ability to dissolve metals such as Zn, Mg, or Fe; ability to release a gasA state of matter in which a substance occupies the full volume of its container and changes shape to match the shape of the container. In a gas the distance between particles is much greater than the diameters of the particles themselves; hence the distances between particles can change as necessary so that the matter uniformly occupies its container. from solidA state of matter having a specific shape and volume and in which the particles do not readily change their relative positions. limestone (CaCO3) or other carbonates; ability to change the color of certain dyes (litmus paper turns red in the presence of acid). Another groupThose elements that comprise a single column of the periodic table. Also called family. of substances called bases or alkalies can also be distinguished by the properties of their aqueous solutions.
These are bitter taste, slippery or soapy feel, and the ability to change the color of certain dyes (litmus paper turns blue in base). Most important of all, acids and bases appear to be opposites. Any acid can counteract or neutralize the properties of a base. Similarly any base can neutralize an acid.