Hydroxyl

HYDROXYL, or water residue, the atomic group OH, which is part of a large number of chemical compounds, for example, NaOH, C₂H₅OH. This group, having unsaturated valence, cannot exist as such in a free state: it is not a chemical individual, but in chemical transformations it mostly reacts as a whole, passing from one compound to another - it plays the role of an element. For example: C₂H₅OH+HJ → C₂H₅J+H₂OH; water can be considered as consisting of hydrogen and a hydroxyl residue: H-ON; hydrates of basic oxides are constructed from metal and one or more hydroxyl residues, for example: NaOH, Ca(OH)₂, Al(OH)₃, etc. Alcohols are products of the replacement of hydrogen atoms by hydroxyl in hydrocarbons, for example: C₂H₅OH (ethyl alcohol), CH₃OH (methyl alcohol). The presence of a hydroxyl group gives certain chemical properties to the compounds of which it is a part; thus, hydrocarbons containing a hydroxyl group form the class of alcohols, with all their characteristic properties. The basic properties of basic hydrates are determined by the hydroxyl group. The latter, as is known, have the ability to dissociate, to break down in an aqueous solution into a positive metal ion and a negative - 'hydroxyl ion': NaOH → Na⁺ + OH^-. Thus, the hydroxyl group, which cannot, as indicated above, exist in a free state, forms a stable hydroxyl ion OH^-, i.e., hydroxyl carrying a negative charge. The hydroxyl ion is the carrier of basic properties: a solution containing free hydroxyl ions has alkaline properties. In a physiological respect, it appears somewhat difficult to establish the role of H. as an ion, since in aqueous solutions the concentration of hydroxyl ions is inversely related to the concentration of hydrogen ions, and phenomena observed when the concentration of OH^- ion increases can be interpreted as a consequence of a decrease in the concentration of H⁺ ion. In any case, numerous experiments (the most important works belong to Loeb and Warburg) have shown that an increase in alkalinity, i.e., an increase in the concentration of OH^- ions, significantly increases the intensity of life processes: the mobility of spermatozoa is accelerated or restored, the vital activity of paramecia increases, oxidative processes (for example, respiration of the eggs of some lower animals) are also significantly enhanced. There are indications that under the influence of increased alkalinity, the breakdown of blood plates occurs, as a result of which blood clotting is accelerated.