Question

action of fused NaOH on Arsenic and nitrogen on lithium.

Answer 1

H3AsO4+2Naoh--->Na2HAso4+2 H2O

And when No reacts wit lithium

6Li+N2--->2Li3N

Answer 2

Sodium Hydroxide is a base while lithium is a metal.  The reaction of the two in presence of Nitrogen may result to the following. The Nitrogen will react with the oxygen in the base to form a brown nitrogen 4 Oxide gas which may be emitted to the enivronment Sodium being a better reactant than lithium may turn togeher and find ways for themselves.