When non-metals combine with oxygen, they typically form acidic oxides. These oxides are also known as non-metallic or acidic anhydrides. The resulting compounds, when dissolved in water, produce acidic solutions. The acidic nature arises because non-metal oxides tend to react with water to form acids.
For example:
Carbon Dioxide (CO₂): \(3CO_2+H_2O→H_2CO_3\)
Carbon dioxide dissolves in water to form carbonic acid.
Sulfur Dioxide (SO₂): \(3SO_2+H_2O→H_2SO_3\)
Sulfur dioxide dissolves in water to form sulfurous acid.
Nitrogen Dioxide (NO₂): \(2NO_2+H_2O→2HNO_3\)
Nitrogen dioxide dissolves in water to form nitric acid.