Page 25 - 6273

To write the acid residue formula it is necessary to add a molecule of water to

the formula of acidic oxide forming an acid formula.

3 Interaction with amphoteric oxides (hydroxides) forming salts:

Na 2O + Cr 2O 3 = 2NaCrO 2,

(Cr 2O 3 + H 2O → H 2Cr 2O 4 = 2HСrO 2).

In the aforementioned reaction, the amphoteric oxide of Cr 2O 3 evinces acidic

properties. Oxides are called acids if they react with substances of the basic

nature.

Chemical properties of acid oxides

1 Interaction with bases forming salt and water:

N 2O 5 + 2NaOH = 2NaNO 3 + H 2O,

(N 2O 5 + H 2O → H 2N 2O 6 = 2HNO 3).

2 Interaction with the main and amphoteric oxides forming salt:
CO 2 + CaO = CaCO 3,

(CO 2 + H 2O → H 2CO 3),
SrO + Al 2O 3 = Sr (AlO 2) 2,

(Al 2O 3 + H 2O → H 2Al 2O 4 = 2HA1O 2).
Oxides are called amphoteric if they, depending on the conditions, evince the

properties of acid or basic oxides.

Chemical properties of amphoteric oxides

3. Interaction with acids or acid oxides forming salts:

ZnO + H 2SO 4 = ZnSO 4 + H 2O.

Al 2O 3 + 3N 2O 5 = 2Al(NO 3) 3

(N 2O 5 + H 2O → 2HNO 3).

2. Interaction with the bases or basic oxides forming salts:

BeO + 2NaOH = Na 2BeO 2 + H 2O,

(BeO + H 2O → H 2BeO 2).

PbO + MgO = MgPbO 2,

(PbO + H 2O → H 2PbO 2)

25