substances or combinations of

substances in aqueous solution imparts to

the system the ability to maintain a desired

pH at a relatively constant level, even with

the addition of materials that may be

expected to change the hydrogen–ion

concentrationsubstances or combinations of

substances in aqueous solution imparts to

the system the ability to maintain a desired

pH at a relatively constant level, even with

the addition of materials that may be

expected to change the hydrogen–ion

concentration