Lapis lazuli is

Metaphosphoric acid has the formula

Which of the following represents the correct order of the inert pair effect in Group $13$ elements?

Nitrogen is a relatively inactive element because

Which of the following statements is incorrect for nitrogen dioxide $(NO_2)$?

$8 NH_{3} + 3 Cl_{2} \rightarrow X$ (Excess $NH_{3}$)
$NH_{3} + 3 Cl_{2} \rightarrow Y$ (Excess $Cl_{2}$)
What are $X$ and $Y$ in the above reactions?