and its conjugate base is nitrate (). The water molecule acts as a base because it receives the hydrogen cation (proton) and its conjugate acid is the hydronium ion (). Applications One use of conjugate acids and bases lies in buffering systems, which include a buffer solution. In a buffer, a weak acid and its conjugate base (in the form of a salt), or a weak base and its conjugate acid, are used in order to limit the pH change during a titration process. Buffers have both organic and non-organic chemical applications. For example, besides buffers being used in lab processes, human blood acts as a buffer to maintain pH. The most important buffer in our bloodstream is the carbonic acid-bicarbonate buffer, which prevents drastic pH changes when is introduced. This functions as such: CO2 + H2O <=> H2CO3 <=> HCO3^- + H+ Furthermore, here is a table of common buffers. A second common application with an organic compound would be the production of a buffer with acetic acid. If acetic acid, a weak acid with the formula , was made into a buffer solution, it would need to be combined with its conjugate base in the form of a salt. The resulting mixture is called an acetate buffer, consisting of aqueous and aqueous . Acetic acid, along with many other weak acids, serve as useful components of buffers in different lab settings, each useful within their own pH range. Ringer's lactate solution is an example where the conjugate base of an organic acid, lactic acid, is combined with sodium, calcium and potassium cations and chloride anions in distilled water which together form a fluid which is isotonic in relation to human blood and is used for fluid resuscitation after blood loss due to trauma, surgery, or a burn injury. Table of acids and their conjugate bases Tabulated below are several examples of acids and their conjugate bases; notice how they differ by just one proton (H+ ion). Acid strength decreases and conjugate base strength increases down the table. Table of bases and their conjugate acids In contrast, here is a table of bases and their conjugate acids. Similarly, base strength decreases and conjugate acid strength increases down the table. See also Buffer solution Deprotonation Protonation Salt (chemistry) References External links MCAT General Chemistry Review - 10.4 Titration and Buffers The Pharmaceutics and Compounding Laboratory - Buffers and Buffer Capacity.