Acids, Bases & pH
Acids release hydrogen ions in solution and read below 7 on the pH scale; bases accept hydrogen ions (or release hydroxide) and read above 7; pure water is neutral at 7.
Acid plus base neutralizes to salt plus water. Buffers resist pH change by soaking up added acid or base — the bicarbonate buffer keeps blood in its narrow range, and the body treats deviations as emergencies.