Question

how can we say that mixture of n2 and o2 follow daltons law of partial pressure?

Answer 1

According to Dalton’s Law, the total pressure inside a container is obtained by adding all the partial pressures of each non-reacting gas. 
so oxygen and nitrogen are non reacting gas

Answer 2

Answer:

no , we cannot apply dalton's law of partial pressure for hydrogen and nitrogen because hydrogen and nitrogen gas may have some force of attraction between them and Dalton law of partial pressure don't apply, when there is a force of attraction.