Oxides of Group elements
The table below summarises the acid-base properties of the common oxides of the Group elements.
Where appropriate, the nature of the species in aqueous solution is also given.
The oxide and the species in aqueous solution are connected by a chemical reaction.
For an acidic oxide:
CO2(g) + H2O(l)
H2CO3(aq)
at pH 7
H2CO3 (aq) + OH–(aq) HCO3–(aq) + H2O(l)
at higher pH
HCO3–(aq) + OH–(aq) CO32–(aq) + H2O(l)
For an amphoteric oxide:
SnO(s) + 2H+(aq) Sn2+(aq) + 2H2O(l)
SnO(s) + H2O(l) + OH– (aq) Sn(OH)3–(aq)
Where appropriate, the nature of the species in aqueous solution is also given.
| nonmetal oxides |
| C |
| acidic gas* CO2 CO32– HCO3– |
| CO gas neither acidic nor basic |
| metalloid oxides | |
| Si | Ge |
| SiO2 acidic solid* SiO32– (polymeric) | GeO2 acidic solid |
| none | GeO amphoteric solid Ge2+ Ge(OH)3– |
| metal oxides | |
| Sn | Pb |
| SnO2 amphoteric solid | PbO2 amphoteric solid |
| SnO amphoteric solid Sn2+ Sn(OH)3– | PbO amphoteric solid Pb2+ Pb(OH)3– |
The oxide and the species in aqueous solution are connected by a chemical reaction.
For an acidic oxide:
CO2(g) + H2O(l)
H2CO3(aq)at pH 7
H2CO3 (aq) + OH–(aq)
HCO3–(aq) + H2O(l)at higher pH
HCO3–(aq) + OH–(aq)
CO32–(aq) + H2O(l)For an amphoteric oxide:
SnO(s) + 2H+(aq)
Sn2+(aq) + 2H2O(l)SnO(s) + H2O(l) + OH– (aq)
Sn(OH)3–(aq)