ABSTRACT
Biochemical reactions occurring in bioenergetics obey the same principles as do the chemical ones. This chapter recalls some essential points concerning the principal chemical equilibria occurring in water and encountered during the evolution of the biochemical reactions. The acid-base and the redox reactions in water are developed. The chapter facilitates the prediction of the directions of the reactions of bioenergetics, that is to say to facilitate their forecasting. Arrhenius’ theory only applies to aqueous solutions. It permits to correctly predict acid-base reactions (in water) included from the quantitative standpoint. In principle, the pH value quantifies the activity of the solvated proton in a solution. This activity can be considered as being the absolute acidity of the solution. Most often, it is an aqueous solution, but the pH is also defined for some other solvents. The matter of predicting reactions is to foresee if they are possible in a given direction and also to know their quantitative character.
