Acids are called complex compounds, which include hydrogen atoms having the ability to be replaced by metal atoms, and an acid residue.
Acids are electrolytes. The chemical properties of acids are determined by their composition.
Classify acids according to various signs:
1. By the number of hydrogen atoms.
2. By the presence of oxygen atoms.
3. According to the degree of dissociation.
By the number of oxygen atoms (the chemical properties of acids depend on this) they are divided into oxygen-free (hydrogen sulfide, hydrochloric, etc.) and oxygen-containing (nitrogen, sulfur, silicon, etc.)
By the number of hydrogen atoms, acids are:
- monobasic, containing one hydrogen atom (hydrochloric, nitrogen);
- dibasic, containing two hydrogen atoms (sulfuric, hydrogen sulfide);
- tribasic, containing three hydrogen atoms (orthophosphoric).
According to the third criterion, acids are divided into weak electrolytes (phosphoric, carbonic, etc.) and strong electrolytes (hydrochloric, nitric, sulfuric).
Chemical properties of acids
The presence of hydrogen ions in acid solutions determines their acidic environment and acidic taste. However, you can’t try them on the tongue, as a chemical burn is possible .
Indicators litmus and methyl orange under the influence of acids change their color.
Acid solutions react with basic oxides to form salt and water.
Acids react with metals to the left of the hydrogen element in a series of metal voltages. The result is a metal salt and hydrogen.
Acids react with bases. The reaction produces salt and water. The interaction between acid and alkali (base) is called a neutralization reaction.
Acids react with salt solutions when the condition for the appearance and flow of the ion exchange reaction to the end is met, that is, a precipitate or gas is released.
The chemical properties of organic acids have their own characteristics.
Phosphoric Acid Properties
Phosphoric acid and its aqueous solutions are much weaker than acids such as nitric and sulfuric. This is an acid that contains three oxygen atoms. The electrolytic dissociation of phosphoric acid occurs in steps. A typical acid is phosphoric acid, chemical properties are determined by its composition.
In a solution of phosphoric acid, dihydrogen phosphate ions are mainly present. The ions that are formed in the second stage of dissociation are much smaller, and phosphate ions, the result of the third stage of ionization, are almost absent. In the first stage, phosphoric acid is an acid of medium strength. Since there are three types of acid residues, the following salts are formed during the interaction of phosphoric acid with alkali: phosphates, hydrogen phosphates and dihydrogen phosphates.
Phosphoric acid can be distinguished from another acid by its interaction with silver nitrate, which results in a yellow precipitate. Other phosphoric acids, interacting with silver nitrate, form a white precipitate. Phosphoric acid, when heated, cleaves water and forms pyrophosphoric acid.
Chemical properties of hydrochloric acid
Hydrochloric acid is a strong monobasic acid with typical acid properties. A colorless, slightly smoking liquid, a solution of hydrogen chloride in water. Hydrochloric acid salts are called “chlorides”.
Hydrochloric acid can be obtained by the interaction of solutions of sodium chloride and sulfuric acid, as well as by dissolving hydrogen chloride in water. Hydrochloric acid reacts with bases, resulting in the formation of salts and water. When interacting with alkali, a neutralization reaction occurs. This can be checked by the indicator. Its color will change, confirming the neutrality of the solution.
The reaction of hydrochloric acid and silver nitrate leads to the formation of an insoluble salt - silver chloride, which precipitates.
Hydrochloric acid reacts with active metals. If zinc is placed in its solution, the active formation and evolution of hydrogen will begin.
Hydrochloric acid, as a typical acid, reacts with bases, metals and salts.