Question

What happens when alkali metals react first with liquid nitrogen and after that recats with oxygen ??​

Answer 1

it react first with oxygen.

it react vigorously and often violently with water to release hydrogen and form strong caustic solution.

Answer 2

When Alkali metals react with Liquid nitrogen & oxygen they form oxide.

For example :-

Li + liq. NH3 + O2 ==> K2O

Similarly all other alkali metals react.