Buffer Solution in Chemistry ( Larutan Buffer dalam ilmu kimia)

A buffer solution or larutan buffer (indonesian)is an aqueous solution consisting of a mixture of a weak acid and its conjugate base or a weak base and its conjugate acid. It has the property that the pH of the solution changes very little when a small amount of strong acid or base is added to it. Buffer solutions are used as a means of keeping pH at a nearly constant value in a wide variety of chemical applications. Many life forms thrive only in a relatively small pH range; an example of a buffer solution is blood.

Buffer solutions are used to maintain a certain level on the pH scale.

Applications

Their resistance to changes in pH makes buffer solutions very useful for chemical manufacturing and essential for many biochemical processes. The ideal buffer for a particular pH has a pKa equal to that pH, since such a solution has maximum buffer capacity.

Buffer solutions are necessary to keep the correct pH for enzymes in many organisms to work. Many enzymes work only under very precise conditions; if the pH strays too far out of the margin, the enzymes slow or stop working and can denature, thus permanently disabling its catalytic activity.[2] A buffer of carbonic acid (H2CO3) and bicarbonate (HCO3−) is present in blood plasma, to maintain a pH between 7.35 and 7.45.

Industrially, buffer solutions are used in fermentation processes and in setting the correct conditions for dyes used in colouring fabrics. They are also used in chemical analysis[1] and calibration of pH meters.

The majority of biological samples that are used in research are made in buffers, especially phosphate buffered saline (PBS) at pH

Useful buffer mixtures :

| Components | pH range |

HCl, Sodium citrate 1 - 5
Citric acid, Sodium citrate 2.5 - 5.6
Acetic acid, Sodium acetate 3.7 - 5.6
K2HPO4, KH2PO4 5.8 - 8 [3]
Na2HPO4, NaH2PO4 6 - 7.5 [4]
Borax, Sodium hydroxide 9.2 - 11