Not a single process in the world is possible without the intervention of chemical compounds, which, reacting with each other, create the basis for favorable conditions. All elements and substances in chemistry are classified according to the structure and functions they perform. The main ones are acids and bases. When they interact, soluble and insoluble s alts are formed.
Examples of acids, s alts
An acid is a complex substance that contains one or more hydrogen atoms and an acid residue in its composition. A distinctive property of such compounds is the ability to replace hydrogen with a metal or some positive ion, resulting in the formation of the corresponding s alt. Almost all acids, with the exception of some (H2SiO3 - silicic acid), are soluble in water, and strong ones, such as HCl (hydrochloric), HNO3 (nitrogen), H2SO4 (sulphuric), completely decompose into ions. And weak ones (for example, HNO2 -nitrogenous, H2SO3 - sulfurous) - partially. Their pH, which determines the activity of hydrogen ions in solution, is less than 7.
S alt is a complex substance, most often consisting of a metal cation and an anion of an acid residue. Usually it is obtained by reacting acids and bases. As a result of this interaction, water is still released. S alt cations can be, for example, cations NH4+. They, like acids, can dissolve in water with varying degrees of solubility.
Examples of s alts in chemistry: CaCO3 - calcium carbonate, NaCl - sodium chloride, NH4Cl - ammonium chloride, K 2SO4 – potassium sulfate and others.
Classification of s alts
Depending on the amount of substitution of hydrogen cations, the following categories of s alts are distinguished:
- Medium - s alts in which hydrogen cations are completely replaced by metal cations or other ions. Such examples of s alts in chemistry can serve as the most common substances that are most common - KCl, K3PO4.
- Acidic - substances in which hydrogen cations are not completely replaced by other ions. Examples are sodium bicarbonate (NaHCO3) and potassium hydrogen orthophosphate (K2HPO4).
- Basic - s alts in which acidic residues are not completely replaced by a hydroxo group with an excess of base or lack of acid. These substances include MgOHCl.
- Complex s alts: Na[Al(OH)4],K2[Zn(OH)4].
Depending on the amount of cations and anions present in the composition of the s alt, they distinguish:
- Simple - s alts containing one type of cation and anion. S alt examples: NaCl, K2CO3, Mg(NO3)2.
- Double - s alts that consist of a pair of types of positively charged ions. These include aluminum-potassium sulfate.
- Mixed - s alts in which there are two types of anions. Examples of s alts: Ca(OCl)Cl.
Getting s alts
These substances are obtained mainly by reacting an alkali with an acid, resulting in water: LiOH + HCl=LiCl + H2O.
When acidic and basic oxides interact, s alts are also formed: CaO + SO3=CaSO4.
They are also obtained by the reaction of an acid and a metal that stands before hydrogen in the electrochemical series of voltages. As a rule, this is accompanied by gas evolution: H2SO4 + Li=Li2SO 4 + H2.
When bases (acids) interact with acidic (basic) oxides, the corresponding s alts are formed: 2KOH + SO2=K2SO 3 + H2O; 2HCl + CaO=CaCl2 + H2O.
Basic reactions of s alts
When a s alt and an acid react, another s alt and a new acid are obtained (the condition for such a reaction is that a precipitate or gas should be released as a result): HCl + AgNO3=HNO3 + AgCl.
When reacting two different soluble s alts get: CaCl2 + Na2CO3=CaCO3 + 2NaCl.
Some s alts that are poorly soluble in water have the ability to decompose into the corresponding reaction products when heated: CaCO3=CaO + CO2.
Some s alts can undergo hydrolysis: reversibly (if it is a s alt of a strong base and a weak acid (CaCO3) or a strong acid and a weak base (CuCl2)) and irreversibly (s alt of a weak acid and a weak base (Ag2S)). S alts of strong bases and strong acids (KCl) do not hydrolyze.
They can also dissociate into ions: partially or completely, depending on the composition.
