Question

What type of oxides are formed when non-metals react with oxygen? Explain with an example.

Answer 1

Non-metals react with oxygen to form acidic oxides or neutral oxides. For example, sulphur reacts with oxygen to form sulphur dioxide. This oxide turns a blue litmus solution red, which shows that it is an acidic oxide.

Carbon is a non-metal. When carbon burns in air, it reacts with the oxygen in the air to form an acidic oxide called carbon dioxide.

\[\ce{\underset{(Non-metal)}{\underset{Carbon}{C_{(s)}}} + \underset{(From air)}{\underset{Oxygen}{O2_{(g)}}} -> \underset{(Acidic oxide)}{\underset{Carbon dioxide}{CO2_{(g)}}}}\]

The acidic oxide, carbon dioxide, dissolves in water to form carbonic acid.

\[\ce{\underset{(Acidic oxide)}{\underset{Carbon dioxide}{CO2_{(g)}}} + \underset{Water}{H2O_{(l)}} -> \underset{(An acid)}{\underset{Carbonic acid}{H2CO3_{(aq)}}}}\]

A solution of carbon dioxide gas in water turns blue litmus paper red, indicating that it is acidic.