An oxide is a compound that is made up of O₂ and one other element. There are four important types of oxides:

• Basic Oxides

A basic oxide is one that reacts with an acid to form salt acid and water only. Basic oxides are usually oxides of metals.

CuO(s)+H2SO4 (aq)→CuSO4 (s)+H2O(l)

When soluble in water, these oxides form alkalis.

Na2O(s)+H2O(l)→2NaOH(aq)

CaO(s)+H20(l)→Ca(OH)2 (aq)

• Acidic Oxides

The acidic oxide is one that reacts with a base to form salt and water. They are usually the oxides of non-metals.

CO2 (g)+2NaOH(aq)→Na2CO3 (s)+H2O(l)

When those oxides are soluble in water, they form acidic solutions.

SO2 (g)+H2O(l)→H2SO3 (aq)

CO2 (g)+H2O(l)→H2CO3 (aq)

• Amphoteric Oxides

It is an oxide has both basic and acidic properties. It reacts with strong acids and bases to form a salt and water only (Semi oxides or metalloids). Eg: Al₂O₃, ZnO, PbO.

• Neutral Oxides

It is one neither has acidic or basic properties. Eg: CO, NO. Another form of oxide is hydrogen peroxide that is a colorless liquid. It is weakly acidic and decomposes slowly at room temperature.

2H2O2 (aq)→2H2O(l)+O2 (g)

Hydrogen peroxide is an oxidizing agent

Test for Oxygen

When a glowing splint is inserted in test tube containing oxygen, it relights it.