Reactions with amphoteric oxides are chemical phenomena in which this class of oxides are reactants in a medium with a inorganic base or one inorganic acid.
Note:amphoteric oxides they are those that have in their constitution only the elements zinc, lead, beryllium and tin.
Regardless of the reaction with amphoteric oxide present as the second reactant an acid or a base, the products formed in this type of reaction will always be the same, that is, a salt and water, as shown in the generic equation below:
amphoteric oxide + acid → salt + H2O
or
amphoteric oxide + base → salt + H2O
Reactions of amphoteric oxides with acid
When an amphoteric oxide reacts with acid (HX), it forms a salt and water. This salt is formed by the interaction between the cation (Y) of the oxide and the anion (X) of the acid, and water is produced in the interaction between the hydrogen in the acid and the oxygen in the oxide, as can be seen in equation below:
YO + HX → YX + H2O
If amphoteric lead oxide IV (PbO2) react with phosphoric acid (H3DUST4), for example:
PbO2 + H3DUST4 →
We will have the formation of the IV lead phosphate salt [Pb3(DUST4)4] from the interaction of the Pb cation+4 of the oxide with the phosphate anion (PO4-3) of the acid, and the interaction of the hydronium cation (H+) of the acid with the anion (O-2) of the oxide. Thus, the balanced equation of this process will be:
3 PbO2+ 4 hours3DUST4 → Pb3(DUST4)4 + 6 H2O
Amphoteric oxide based reactions
When the amphoteric oxide reacts with an inorganic base (WOH), salt and water will form, as shown in the generic equation below:
YO + WOH → WYOno + H2O
Salt is formed from the interaction between the cation (W+) of the base with the anion (Yono), formed by the metal present in the oxide. Below, see a list containing the anions formed by the common metals of amphoteric oxides:
Table with anions formed by some metals
If, for example, aluminum oxide (Al2O3) react with barium hydroxide [Ba(OH)2]:
Al2O3 + Ba(OH)2 →
The barium cation (Ba+2) of the base must interact with the aluminate anion (AlO2-1), formed by the aluminum present in the oxide, which will give rise to the barium aluminate salt [Ba (AlO2)2], and water will be formed from the base hydroxyls. Check out the balanced equation for this process below:
1 Al2O3 + 1 Ba (OH)2 → 1 Ba (AlO2)2 + 1 hour2O
By Me. Diogo Lopes Dias
Source: Brazil School - https://brasilescola.uol.com.br/quimica/reacoes-com-oxidos-anfoteros.htm
