Question

Explain the different types of oxides with suitable examples

Answer 1

Acidic Oxides
Acidic oxides are the oxides of non-metals (Groups 14-17) and these acid anhydrides form acids with water:

Sulfurous Acid
SO2+H2O→H2SO3(1.1)
(1.1)SO2+H2O→H2SO3
Sulfuric Acid
SO3+H2O→H2SO4(1.2)
(1.2)SO3+H2O→H2SO4
Carbonic Acid
CO2+H2O→H2CO3(1.3)
(1.3)CO2+H2O→H2CO3
Acidic oxides are known as acid anhydrides (e.g., sulfur dioxide is sulfurous anhydride and sulfur trioxide is sulfuric anhydride) and when combined with bases, they produce salts, e.g.,

SO2+2NaOH→Na2SO3+H2O(1.4)
(1.4)SO2+2NaOH→Na2SO3+H2O
Basic Oxides
Generally Group 1 and Group 2 elements form bases called base anhydrides or basic oxides e.g.,

K2O(s)+H2O(l)→2KOH(aq)(1.5)
(1.5)K2O(s)+H2O(l)→2KOH(aq)
Basic oxides are the oxides of metals. If soluble in water, they react with water to produce hydroxides (alkalies) e.g.,

CaO+H2O→Ca(OH)2(1.6)
(1.6)CaO+H2O→Ca(OH)2
MgO+H2O→Mg(OH)2(1.7)
(1.7)MgO+H2O→Mg(OH)2
Na2O+H2O→2NaOH(1.8)
(1.8)Na2O+H2O→2NaOH
These metallic oxides are known as basic anhydrides. They react with acids to produce salts, e.g.,

MgO+2HCl→MgCl2+H2O(1.9)
(1.9)MgO+2HCl→MgCl2+H2O
Na2O+H2SO4→Na2SO4+H2O(1.10)
(1.10)Na2O+H2SO4→Na2SO4+H2O
Amphoteric Oxides
An amphoteric solution is a substance that can chemically react as either acid or base. For example, when HSO4- reacts with water it will make both hydroxide and hydronium ions:

HSO−4+H2O→SO2−4+H3O+(1.11)
(1.11)HSO4−+H2O→SO42−+H3O+
HSO−4+H2O→H2SO4+OH−(1.12)
(1.12)HSO4−+H2O→H2SO4+OH−
Amphoteric oxides exhibit both basic as well as acidic properties. When they react with an acid, they produce salt and water, showing basic properties. While reacting with alkalies they form salt and water showing acidic properties.

For example ZnOZnO exhibits basic behavior with HClHCl
ZnO+2HCl→ZnCl2zincchloride+H2O(basicnature)(1.13)
(1.13)ZnO+2HCl→ZnCl2zincchloride+H2O(basicnature)
and acidic behavior with NaOHNaOH
ZnO+2NaOH→Na2ZnO2sodiumzincate+H2O(acidicnature)(1.14)
(1.14)ZnO+2NaOH→Na2ZnO2sodiumzincate+H2O(acidicnature)
Similarly, Al2O3Al2O3 exhibits basic behavior with H2SO4H2SO4
Al2O3+3H2SO4→Al2(SO4)3+3H2O(basicnature)(1.15)
(1.15)Al2O3+3H2SO4→Al2(SO4)3+3H2O(basicnature)
and acidic behavior with NaOHNaOH
Al2O3+2NaOH→2NaAlO2+H2O(acidicnature)(1.16)
(1.16)Al2O3+2NaOH→2NaAlO2+H2O(acidicnature)
Neutral Oxides
Neutral oxides show neither basic nor acidic properties and hence do not form salts when reacted with acids or bases, e.g., carbon monoxide (CO); nitrous oxide (N2O); nitric oxide (NO), etc., are neutral oxides.

Peroxides and Dioxides
Oxides: Group 1 metals react rapidly with oxygen to produce several different ionic oxides, usually in the form of M2OM2O. With the oyxgen exhibiting an oxidation number of -2.

4Li+O2→2Li2O(1.17)
(1.17)4Li+O2→2Li2O
Peroxides: Often Lithium and Sodium reacts with excess oxygen to produce the peroxide, M2O2M2O2. with the oxidation number of the oxygen equal to -1.

H2+O2→H2O2(1.18)
(1.18)H2+O2→H2O2
Superoxides: Often Potassium, Rubidium, and Cesium react with excess oxygen to produce the superoxide, MO2MO2. with the oxidation number of the oxygen equal to -1/2.

Cs+O2→CsO2(1.19)
(1.19)Cs+O2→CsO2
A peroxide is a metallic oxide which gives hydrogen peroxide by the action of dilute acids. They contain more oxygen than the corresponding basic oxide, e.g., sodium, calcium and barium peroxides.

BaO2+H2SO4→BaSO4+H2O2(1.20)
(1.20)BaO2+H2SO4→BaSO4+H2O2
Na2O2+H2SO4→Na2SO4+H2O2(1.21)
(1.21)Na2O2+H2SO4→Na2SO4+H2O2
Dioxides like PbO2 and MnO2 also contain higher percentage of oxygen like peroxides and have similar molecular formulae. These oxides, however, do not give hydrogen peroxide by action with dilute acids. Dioxides on reaction with concentrated HCl yield Cl2 and on reacting with concentrated H2SO4 yield O2.

PbO2+4HCl→PbCl2+Cl2+2H2O(1.22)
(1.22)PbO2+4HCl→PbCl2+Cl2+2H2O
2PbO2+2H2SO4→2PbSO4+2H2O+O2(1.23)
(1.23)2PbO2+2H2SO4→2PbSO4+2H2O+O2
Compound Oxides
Compound oxides are metallic oxides that behave as if they are made up of two oxides, one that has a lower oxidation and one with a higher oxidation of the same metal, e.g.,

Red lead: Pb3O4=PbO2+2PbO(1.24)
(1.24)Red lead: Pb3O4=PbO2+2PbO
Ferro-ferric oxide: Fe3O4=Fe2O3+FeO(1.25)
(1.25)Ferro-ferric oxide: Fe3O4=Fe2O3+FeO
On treatment with an acid, compound oxides gi