A non metal A the largest constituent of air, when heated with hydrogen in the 1:3 ratio in the presence of Fe as catalyst, gives a gas B. On heating with oxygen it gives an oxide C. If this oxide is passed through water in the presence of oxygen it gives an acid D, a strong oxidizing agent.
a. Identify A,B,C and D
b. To which group of the periodic table does this non metal belong?

Explanation

a. A: Nitrogen `B: NH_(3):C:NO:D:HNO_(3)`
b. Group 15.