Question

Pure nitrogen is obtained by decomposition of nitride $M_x\left(N_3\right)y$ where, $x+y=?$

Answer 1

$2Na{N}_3\left(s\right)\to 2Na\left(s\right)+3N_2\left(g\right)$
As pure Nitrogen is obtained by decompostion of Sodium azide ($Na{N}_3$), as shown above.
So, $Mx\left(N_3\right)y$ = M1($N_3$)1 = Na1($N_3$)1
so, $x=1$ and $y=1$.