CoachThe pH of an aqueous solution is a number, usually between 0 and 14, that tells how acidic or basic it is: at , a neutral solution has pH 7, an acidic solution a pH below 7, a basic solution a pH above 7. The more ions a solution holds, the lower its pH.
Examples
Example 18.8 (The pH of the ocean)
The average pH of the ocean is about 8.1: slightly basic. Since the industrial era began, carbon dioxide dissolving from the air has lowered the pH of surface waters by about 0.1: the oceans are slowly becoming less basic, which harms shellfish and corals.