Electrical dissociation plays a huge rolein our lives, although we usually do not think about it. It is with this phenomenon that the conductivity of salts, acids and bases in a liquid medium is related. From the first heart rhythms, conditioned by "live" electricity in the human body, eighty percent of which consists of liquids, to cars, mobile phones and players, whose batteries are inherently electrochemical elements of nutrition, there is an invisible electrical dissociation near us.
In the giant vapors emitting poisonous vaporsfrom molten high-temperature bauxite electrolysis method, "winged" metal-aluminum is produced. All the objects around us, from chrome gratings of radiators to silvered earrings in the ears, have ever encountered solutions or melts of salts, and hence, with this phenomenon. Knowingly electrical dissociation is studied by the whole branch of science - electrochemistry.
When dissolving the liquid-solvent moleculeenter into a chemical bond with the molecules of the solute, forming solvates. In an aqueous solution of dissociation, salts, acids and bases are most susceptible. As a result of this process, the molecules of the dissolved substance can decay into ions. For example, under the influence of an aqueous solvent, Na ions+ and CI-, located in the ionic NaCl crystal, pass into the solvent medium in an already new quality of solvated (hydrated) particles.
This phenomenon, which in its essence is a processcomplete or partial dissolution of the dissolved substance into ions as a result of the action of the solvent, and is called "electrical dissociation." This process is extremely important for electrochemistry. Of great importance is the fact that the dissociation of complex multicomponent systems is characterized by a step-by-step flow. This phenomenon is also marked by a sharp increase in the number of ions in the solution, which distinguishes electrolytic substances from nonelectrolytic ones.
During the electrolysis, the ions have a clearThe direction of motion: particles with a positive charge (cations) - to a negatively charged electrode, called the cathode, and positive ions (anions) to the anode, an electrode with the opposite charge, where their discharge occurs. Cations are reduced, and the anions are oxidized. Therefore, dissociation is a reversible process.
One of the fundamental characteristics of thiselectrochemical process is the degree of electrolytic dissociation, which is expressed by the ratio of the number of hydrated particles to the total number of molecules of the dissolved substance. The higher this value, the stronger the electrolyte is the substance. On this basis, all substances are divided into weak, medium strength and strong electrolytes.
The degree of dissociation depends on the following factors:a) the nature of the solute; b) the nature of the solvent, its dielectric permeability and polarity; c) the concentration of the solution (the lower this value, the greater the degree of dissociation); d) the temperature of the dissolving medium. For example, the dissociation of acetic acid can be expressed by the following formula:
CH3COOH H+ + CH3COO-
Strong electrolytes dissociate practicallyirreversible, since in their aqueous solution there are no original molecules and non-hydrated ions. It should also be added that all substances having an ionic and a covalent polar type of chemical bonds are susceptible to dissociation. The theory of electrolytic dissociation was formulated by the outstanding Swedish physicist and chemist Svante Arrhenius in 1887.
