the term "electrolytic dissociation" scientists work with the late nineteenth century.His appearance we owe Swedish chemist Arrhenius.Working on the problem of electrolytes in the years 1884-1887, he introduced it to describe the phenomenon of ionization in solutions and the formation of melts.The mechanism of this phenomenon, he decided to explain the decomposition of the molecules into ions, elements having positive or negative charge.
theory of electrolytic dissociation explains the conductivity of some solutions.For example, for potassium chloride KCl characterized by disintegration of a molecule of this salt to potassium ion with a charge to the "plus" (cations) and chloride ion, charge with "minus" (anion).Hydrochloric acid decomposes to HCl cation (hydrogen ion) and an anion (chloride ion), sodium hydroxide solution NaHO leads to sodium ion and an anion as hydroxide ion.The main provisions of the theory of electrolytic dissociation, describe the behavior of ions in solutions.According to this theory, they move completely freely within the solution, and even a small drop of the solution is kept uniform distribution of oppositely charged electric charges.
theory of electrolytic dissociation process of the formation of electrolytes in aqueous solutions is explained as follows.The emergence of free ions indicates the destruction of the crystal lattice of substances.The process by dissolving the substance in water is influenced by the impact of polar solvent molecules (in our example, we consider the water).They are capable enough to reduce electrostatic attraction force that exists between the ions in the lattice sites, resulting ions pass to the free movement of the solution.Thus free ions enter the environment polar water molecules.This shell forms around them, the theory of electrolytic dissotsiatsiinazyvaet hydrated.
But the theory of electrolytic dissociation Arrhenius explains the formation of electrolytes not only in solutions.The crystal lattice can be destroyed under the influence of temperature.By heating the crystal, we get the effect of intense vibrations of ions in lattice sites, gradually leading to the destruction of the crystal and the appearance of the melt consist entirely of ions.
Returning to the solutions should consider separately the property of a substance, which we call a solvent.The brightest representative of this family is water.The main feature is the presence of dipolar molecules, ie,when one end of the molecule is positively charged and the other negatively.The water molecule meets these requirements, but the water is not the only solvent.
process of electrolytic dissociation may cause the non-aqueous polar solvents, for example, liquid sulfur dioxide, liquid ammonia and so forth. But that water occupies the number of its principal place because of its property to weaken the (dissolve) the electrostatic attraction and destroy the crystalline lattice appears especially bright.Therefore, speaking of solutions, we mean it is water-based fluid.
thorough study of the properties of electrolytes allowed to move to the concept of power and the degree of dissociation.The degree of dissociation of the electrolyte means the ratio of the number of dissociated molecules to their total number.Potential electrolytes, this coefficient ranges from zero to one, and the degree of dissociation, which is equal to zero, indicates that we are dealing with non-electrolytes.On increasing the degree of dissociation positively affects the temperature rise of the solution.
Force electrolytes determine the degree of dissociation, provided a constant concentration and temperature.Strong electrolytes have a degree of dissociation, approaching unity.It is readily soluble salts, alkalis, acids.
theory of electrolytic dissociation allowed to give an explanation of a broad range of phenomena that are studied in the framework of physics, chemistry, physiology of plants and animals, theoretical electrochemistry.
