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19. BASES. CLASSIFICATION. RECEIVING. PROPERTIES.
The bases are the complex substances consisting of atom of the metal connected with one or several gidroksogruppami-ON. General formula:
According to the nomenclature of the basis call hydroxides:
| Formula | Name | Formula | Name |
| LiOH | lithium hydroxide | Ca(OH)2 | calcium hydroxide |
| NaOH | sodium hydroxide | Cu(OH)2 | copper hydroxide (II) |
| KOH | potassium hydroxide | Fe(OH)2 | ferrous hydroxide (III) |
Carry hydroxides of alkali and alkaline earth metals to alkalis (LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2. The others - insoluble.
Carry so-called amphoteric hydroxides which at interaction with acids act as the basis to insoluble, and with alkali - as acids.Receiving bases.
| Alkalis | 1. Metal + water | 2Na+H2O=2NaOH+H2 Ba+2H2O=Ba(OH)2+H2 |
| 2. Oxide + water | Li2O+H2O=2LiOH CaO+H2O=Ca(OH)2 |
|
| 3. Electrolysis of solutions of alkali metals | 2NaCl+2H2O=2NaOH+Cl2+H2 |
|
| Insoluble bases | Salt + alkali | CuSO4+2NaOH=Cu(OH)2+Na2SO4 |
Chemical properties of the bases.
| Alkalis | Insoluble bases |
| 1. Interaction with acids | |
| KOH+HCl=KCl+H2O | Cu(OH)2+2HCl=CuCl2+2H2O |
| 2. Interaction with acid oxides | |
| 2KOH+CO2=K2CO3+H2O | are not characteristic |
| 3. Operation of indicators | |
| litmus - blue, phenolphthalein - crimson | coloring does not change |
| 4. Interaction with amphoteric oxides | |
| 2KOH+ZnO=K2ZnO2+H2O | do not react |
|
5. Interaction with salts if slightly soluble salt or the slightly soluble basis is formed
|
|
| NaOH+CuCl2=Cu(OH)2=2NaCl | do not react |
| 6. When heating | |
| do not decay (except LiOH) | Cu(OH)2=CuO+H2O |
| Amphoteric hydroxides (Al(OH)3, Zn(OH)2, Be(OH)2, Fe(OH)3 and others. | |
| Interact with acids Zn(OH)2+2HCl=ZnCl2+2H2O |
Interact with alkalis Al(OH)3+NaOH=Na [Al(OH)4] |