In nature, everything is interconnected. A huge role in establishing favorable conditions is played by chemical elements and their compounds among themselves. The most important substances due to which many processes necessary for the existence of living organisms occur are acids, salts and bases.
a brief description of
In chemistry, the definition of bases is as follows: these are substances that have in their composition the OH - hydroxy group, which is cleaved off when it reacts with other reagents. Most often, the bases are in a solid state. Some of them, mainly alkalis, such as NaOH, Ca (OH) 2 , do not decompose even when heated, which indicates their stability. Moreover, alkalis (lithium, sodium, potassium, calcium, ammonium, barium hydroxides) are caustic substances that can harm the skin. They interact very actively with water, so they require more careful use.
According to another definition of bases, they are also called electrolytes, since they are able to dissociate into metal cations (in rare cases, non-metal) and anions - OH hydroxides - when dissolved in water.
Getting
By definition, the bases are divided into soluble (alkali) and insoluble in water. Alkalis can be obtained by reacting the corresponding active metal with water. The reaction is accompanied by the release of hydrogen gas:
2K + 2H 2 O = 2KOH + H 2
Alkalis are also obtained by reaction of an active metal oxide with water:
Li 2 O + H 2 O = 2LiOH
To obtain poorly soluble bases, aqueous solutions of salts act with alkalis:
CuSO 4 + 2 KOH = Cu (OH) 2 + K 2 SO4
There is an industrial method for determining the bases - electrolysis of aqueous solutions of salts. With this method, it is mainly possible to obtain sodium and potassium hydroxides:
2KCl + 2H 2 O = 2KOH + Cl 2 + H 2
Chemical properties
- Interact with acids to form salt and water:
2KOH + H 2 SO4 = K 2 SO4 + 2H 2 O
- When the bases react with acid oxides, the products are also salt and water:
2KOH + SO 3 = K 2 SO4 + H 2 O
- When the bases enter the reaction with the salts, another acid and another base are obtained. In this case, one of the reaction products should precipitate, leaving the solution:
2KOH + CuCl 2 = 2KCl + Cu (OH) 2
- By definition, bases can decompose into the corresponding oxide and water when heated, only if they do not dissolve in water:
Cu (OH) 2 = CuO + H 2 O
There are also bases that possess the properties of both bases and acids. They are called amphoteric and enter into characteristic reactions.
Moreover, these substances can be used in laboratories as accelerators of other chemical reactions, i.e. catalysts.