What is formed when ammonia reacts with excess chlorine gas?

Which one of the following properties is $not$ shown by $NO$?

An orange solid $(X)$ on heating,gives a colourless gas $(Y)$ and a green residue $(Z).$ Gas $(Y)$ on treatment with $Mg,$ produces a white solid substance. Identify the white solid substance.

Which of the following is obtained by catalytic oxidation of ammonia?

What happens when white phosphorus is heated with concentrated $NaOH$ solution in an inert atmosphere of $CO_{2}$?

The molecular formula of metaphosphoric acid is