Each student met with the concept of "oxide" in chemistry classes. From this one word the subject began to seem indescribably scary. But there’s nothing wrong with that. Higher oxides are substances that contain compounds of simple substances with oxygen (in the oxidation state -2). It is worth noting that they react with:
- O 2 (oxygen), in the event that the element is not in higher CO. For example, SO 2 reacts with oxygen (because CO is +4), and SO 3 does not (because it stands in the highest oxidation state +6).
- H 2 (hydrogen) and C (carbon). Only some oxides are reacted.
- Water if soluble alkali or acid is obtained.
All oxides react with salts and non-metals (with the exception of the above substances).
It is worth noting that some substances (for example, nitric oxide, iron oxide and chlorine oxide) have their own characteristics, that is, their chemical characteristics may differ from other substances.
Oxide classification
They are divided into two branches: those who can form salt, and those who cannot form it.
Examples of formulas of higher oxides that do not form salts: NO (two valence nitric oxide; colorless gas produced during thunderstorms), CO (carbon monoxide), N 2 O (monovalent nitric oxide), SiO (silicon oxide), S 2 O (sulfur oxide), water.
These compounds can react with bases, acids, and salt-forming oxides. But when these substances react, salts never form. For instance:
CO (carbon monoxide) + NaOH (sodium hydroxide) = HCOONa (sodium formate)
Salt-forming oxides are divided into three types: acidic, base and amphoteric oxides.
Acid Oxides
An acidic higher oxide is a salt-forming oxide that corresponds to acid. For example, hexavalent sulfur oxide (SO 3 ) has a corresponding chemical compound - H 2 SO 4 . These elements react with oxides of basic and amphoteric properties, bases and water. A salt or acid forms.
- With alkaline oxides: CO 2 (carbon dioxide) + MgO (magnesium oxide) = MgCO 3 (bitter salt).
- With amphoteric oxides: P 2 O 5 (phosphorus oxide) + Al 2 O 3 (aluminum oxide) = 2AlPO 4 (aluminum phosphate or orthophosphate).
- With bases (alkalis): CO 2 (carbon dioxide) + 2NaOH (caustic soda) = Na 2 CO 3 (sodium carbonate or soda ash) + H 2 O (water).
- With water: CO 2 (carbon dioxide) + H 2 O = H 2 CO 3 (carbonic acid, after the reaction instantly decomposes into carbon dioxide and water).
Acid oxides do not react with each other.
Basic oxides
The main higher oxide is the salt-forming metal oxide to which the base corresponds. Calcium hydroxide (CaO) corresponds to calcium hydroxide (Ca (OH) 2 ). These substances interact with oxides of acidic and amphoteric nature, acids (with the exception of H 2 SiO 3 , since silicic acid is insoluble) and water.
- With acid oxides: CaO (calcium oxide) + CO 2 (carbon dioxide) = CaCO 3 (calcium carbonate or ordinary chalk).
- With amphoteric oxide: CaO (calcium oxide) + Al 2 O 3 (alumina) = Ca (AlO 2 ) 2 (calcium aluminate).
- With acids: CaO (calcium oxide) + H 2 SO 4 (sulfuric acid) = CaSO 4 (calcium sulfate or gypsum) + H 2 O.
- With water: CaO (calcium oxide) + H 2 O = Ca (OH) 2 (calcium hydroxide or lime slaking reaction).
Do not interact with each other.
Amphoteric oxides
Amphoteric higher oxide is an amphoteric metal oxide. Depending on the conditions, it may exhibit basic or acidic properties. For example, the formulas of higher oxides that exhibit amphoteric properties: ZnO (zinc oxide), Al 2 O 3 (alumina). Amphoteric oxides react with alkalis, acids (with the exception of silicic acid), basic and acid oxides.
- With bases: ZnO (zinc oxide) + 2NaOH (sodium base) = Na 2 ZnO 2 (double salt of zinc and sodium) + H 2 O.
- With acids: Al 2 O 3 (aluminum oxide) + 6HCl (hydrochloric acid) = 2AlCl 3 (aluminum chloride or aluminum chloride) + 3H 2 O.
- With acidic oxides: Al 2 O 3 (aluminum oxide) + 3SO 3 (hexavalent sulfur oxide) = Al 2 (SO 4 ) 3 (aluminum alum).
- With basic oxides: Al 2 O 3 (aluminum oxide) + Na 2 O (sodium oxide) = 2NaAlO 2 (sodium aluminate).
Elements of higher amphoteric oxides do not interact with each other and with water.