Answer:
Option D
Explanation:
$Ba(N_{3})_{2} \underrightarrow{heat} Ba(s)+3N_{2}(g)$
Azide salt of barium can be obtained in purest form as well as the decomposition product contain solid Ba as byproduct along with gaseous nitrogen, hence no additional step of separation is required. Other reactions are
$NH_{4}NO_{3} \underrightarrow{heat} N_{2}O+2H_{2}O$
$2NH_{3}+3CuO \underrightarrow{heat} 3Cu+3H_{2}O+N_{2}$
$ (NH_{4})_{2}Cr_{2}O_{7} \underrightarrow{heat} Cr_{2}O_{3}+4H_{2}O+N_{2}$
