pH is a measure of how acidic or basic (alkaline) a solution is. It is determined by the concentration of hydrogen ions present in the solution.
Acidic: Solutions with a low pH value (below 7) that have higher concentrations of hydrogen ions.
Basic/Alkaline: Solutions with a high pH value (above 7) that have lower concentrations of hydrogen ions.
Buffer system: A mechanism that helps maintain stable pH levels by resisting changes when acids or bases are added to a solution.