NEEDLE ACID — dibasic acid, H2C03 which is formed at dissolution in water of C02 carbon dioxide; plays an important role in maintenance of acid-base balance at the person and the highest vertebrate animals. Salts U. to., napr, Li2C03 lithium carbonate (see Lithium), in medicine is applied as pharmaceuticals; definition in blood of concentration of anion U. to. — bicarbonate (hydrocarbonate) - an ion has great diagnostic value at establishment of an acid-base condition of an organism (see the Alkalosis, Acidosis) at various diseases leading to disturbance of acid-base equilibrium (see).
At. to. is weak to - that (see Acids and the bases), at pH of blood it dissociates (see Dissociation) with education bicarbonate (hydrocarbonate) - ion НСО^ (see Bicarbonates) and at big cultivation — a carbonate ion of SOD. Balance between C02, coal to - that and bicarbonate ions in the isolated system is established slowly. At the person and animals in erythrocytes bystry establishment of such balance is reached by means of enzyme of a karboangidra-za (see). Regulation of activity of this enzyme specific inhibitors, napr, Diacarbum (see), is used with to lay down. the purpose for achievement of diuretic effect at treatment of glaucoma (see), disturbances of neuromuscular conductivity, etc.
At. to. can form normal (average) salts — carbonates and acid (monosubstituted) salts — bicarbonates (hydrocarbonates). Carbonates are water-insoluble (except for carbonates of alkali metals, and also ammonium carbonates and thallium). Bicarbonates well of a rastvorima in water and during the heating turn into carbonates. At action strong to - t carbonates decay with formation of C02. Na2C03 sodium carbonate (soda) has the broadest industrial use. In the nature mix of a carbonate and sodium bicarbonate contains in mineral waters (see). Many natural carbonates are valuable metal ores, semiprecious ornamental stones, etc.
Carboxylic acids (see) sometimes consider as derivatives At. to. (Latin acidum carbonicum), in to-rykh one hydroxyl (IT is group) is replaced by the hydrocarbon radical. To derivatives At. to.
also poison gas phosgene are (see. Suffocating toxic agents).
See also Buffer systems. Bibliography: Glinka N. L. General
chemistry, L., 1978; To and R. S. N and O. K's Der measures. Introduction to the chemical nomenclature, the lane with English, page 134, 207, M., 1983; Whyte A., etc. Fundamentals of biochemistry, the lane with English, t. 3, page 1218, M., 1981. N. V. Gulyaeva.