Question

Reaction with oxygen or air​

Answer 1

Explanation:

Reaction with oxygen is just a more dramatic version of the reaction with air. Lithium is unique in the Group because it also reacts with the nitrogen in the air to form lithium nitride (again, see below). Lithium burns with a strongly red-tinged flame if heated in air.

Answer 2

Answer:

The reaction with oxygen in the air

It reacts with oxygen in the air to give white lithium oxide. With pure oxygen, the flame would simply be more intense. For the record, it also reacts with the nitrogen in the air to give lithium nitride.