What Is a Buffering Agent?
Buffer is a solid combination that can be used to control the fugacity of gas or liquid under high temperature and pressure, or at normal temperature and pressure. It can be solid or liquid. Buffers in chemical engineering are often referred to as acid-base stabilizers, and are generally salts, such as strong acid, weak base or weak acid and strong base salts, which gradually release the acid or base in the salt during the reaction or preservation to maintain stable acid and base value. [1]
- Oxygen buffer
- Add a small amount of strong acid or alkali to the buffer solution, and the pH value of the solution does not change much, but if an acid is added and the amount of alkali is large,
- In order to prepare a buffer solution of a certain pH, first select a weak acid whose pK a is as close as possible to the pH value of the buffer solution to be prepared, and then calculate the concentration ratio of acid to alkali, and then prepare the required concentration based on this concentration ratio. Buffer solution. Above, a buffer solution composed of a weak acid and its salt is used as an example to explain its working principle, pH calculation and preparation method. The same method can be used for buffer solutions composed of weak bases and their salts.
- Buffer solutions are widely used in material separation and component analysis. For example, when identifying Mg 2+ ions, the following reactions can be used: The precipitation of white magnesium ammonium phosphate is soluble in acid, so the reaction needs to be performed in alkaline solution, but the basicity is too strong White Mg (OH) 2 precipitate may be formed, so the pH of the reaction needs to be controlled within a certain range. Therefore, a buffer solution composed of NH 3 · H 2 O and NH 4 Cl is used to maintain the pH of the solution. reaction.