pH
For other uses, see PH (disambiguation). pH values of some common substances Acids and Bases Acid Acid–base reaction Acid strength Acidity function Amphoterism Base Buffer solutions Dissociation constant Equilibrium chemistry Extraction Hammett acidity function pH Proton affinity Self-ionization of water Titration Lewis acid catalysis Frustrated Lewis pair Chiral Lewis acid Acid types Brønsted Lewis Acceptor Mineral Organic Strong Superacids Weak Solid Base types Brønsted Lewis Donor Organic Strong Superbases Non-nucleophilic Weak v t e In chemistry, pH ( / p iː ˈ eɪ tʃ / ) is a logarithmic scale used to specify the acidity or basicity of an aqueous solution. It is approximately the negative of the base 10 logarithm of the molar concentration, measured in units of moles per liter, of hydrogen ions. More precisely it is the negative of the base 10 logarithm of the activity of the hydrogen ion. [1] At 25 °C, s...