The term "electrolytic dissociation" is understood as the process of decomposition of a substance conducting an electric current into ions.
This process can take place both in solutions and in the melts of matter.
Dissociation of acids, bases, salts. Most salts are strong electrolytes. This means that their solutions or melts conduct a good electric current, due to the formation of a large number of charged particles - ions.
What is the mechanism of dissociation of salts in solutions or melts
Imagine what will happen to a well-known to everyonePeople to salt, if its crystals melt or throw into the water. This substance has the structure of an ionic crystal lattice. During melting, thermal energy will cause the ion oscillations at the lattice sites to multiply many times, as a result of which the bonds between neighboring ions begin to break down. Free ions will appear. And this process with the continuation of heating will continue until the crystal lattice is completely destroyed. A similar mechanism of destruction will be when dissolving crystals of sodium chloride in water, but instead of thermal energy, water molecules act here, as if "stretching" the crystals into separate particles.
The theory of electrolytic dissociation was firstPut forward by two chemists - Arrhenius and Ostwald at the end of the XIX century. It is through dissociation that they describe the properties of salts, as well as bases and acids. Acid and basic salts undergo dissociation stepwise, for example, KHSO4 = K ^ + + HSO4 ^ -
What are the features of dissociation of salts
Dissociation of salts is positively formedCharged metal cations (or ammonium cation), as well as negatively charged cations of acidic residues. The dissociation process proceeds depending on which salt is dissolving or melting (medium, acidic or basic).
If the salt is average (that is, formed by an acid, in the molecules of which all the hydrogen cations are replaced by metal or ammonium cations), dissociation takes place according to such schemes, in one stage:
KNO3 = K ^ ++ NO3 ^ -
Na2SO4 = 2Na ^ ++ SO4 ^ 2-
Acid and basic salts dissociate into severalStages. The acid salt (that is, formed by an acid whose hydrogen cations are not completely replaced) first loses the metal ion, and then the hydrogen cation is split off. For example:
NaHSO4 = Na ^ ++ HSO4 ^ -
HSO4 ^ - = H ^ ++ SO4 ^ 2-
The basic salts (that is, formed by alkalis, in which the hydroxyl groups are not completely replaced), acidic residues are first cleaved off, and then OH-ions. For example:
Cu (OH) Cl = Cu (OH) ^ ++ Cl ^ -
Cu (OH) ^ + = Cu ^ 2 ++ OH ^ -