Term | Definition |
acid ionization | reaction involving the transfer of a proton from an acid to water, yielding hydronium ions and the conjugate base of the acid |
acid ionization constant (Ka) | equilibrium constant for the ionization of a weak acid |
acid-base indicator | organic acid or base whose color changes depending on the pH of the solution it is in |
acidic | describes a solution in which [H3O+] > [OH−] |
amphiprotic | species that may either gain or lose a proton in a reaction |
amphoteric | species that can act as either an acid or a base |
autoionization | reaction between identical species yielding ionic products; for water, this reaction involves transfer of protons to yield hydronium and hydroxide ions |
base ionization | reaction involving the transfer of a proton from water to a base, yielding hydroxide ions and the conjugate acid of the base |
base ionization constant (Kb) | equilibrium constant for the ionization of a weak base |
basic | describes a solution in which [H3O+] < [OH−] |
Brønsted-Lowry acid | proton donor |
Brønsted-Lowry base | proton acceptor |
buffer | mixture of a weak acid or a weak base and the salt of its conjugate; the pH of a buffer resists change when small amounts of acid or base are added |
buffer capacity | amount of an acid or base that can be added to a volume of a buffer solution before its pH changes significantly (usually by one pH unit) |
color-change interval | range in pH over which the color change of an indicator takes place |
conjugate acid | substance formed when a base gains a proton |
conjugate base | substance formed when an acid loses a proton |
diprotic acid | acid containing two ionizable hydrogen atoms per molecule. A diprotic acid ionizes in two steps |
diprotic base | base capable of accepting two protons. The protons are accepted in two steps |
Henderson-Hasselbalch equation | equation used to calculate the pH of buffer solutions |
ion-product constant for water (Kw) | equilibrium constant for the autoionization of water |
leveling effect of water | any acid >H3O+, or any base > OH− will react with water to form H3O+, or OH−, respectively; water acts as a base to make all strong acids appear equally strong, and it acts as an acid to make all strong bases appear equally strong |
monoprotic acid | acid containing one ionizable hydrogen atom per molecule |
neutral | describes a solution in which [H3O+] = [OH−] |
oxyacid | compound containing a nonmetal and one or more hydroxyl groups |
percent ionization | ratio of the concentration of the ionized acid to the initial acid concentration, times 100 |
pH | logarithmic measure of the concentration of hydronium ions in a solution |
pOH | logarithmic measure of the concentration of hydroxide ions in a solution |
stepwise ionization | process in which an acid is ionized by losing protons sequentially |
titration curve | plot of the pH of a solution of acid or base versus the volume of base or acid added during a |
titration | triprotic acid acid that contains three ionizable hydrogen atoms per molecule; ionization of triprotic acids occurs in three steps |