Question

Extra pure $N_2$ can be obtained by heating

• A. $NH_3$ with $CuO$
• B. $NH_4NO_3$
• C. $(NH_4 ),Cr_2 O_7$
• D. $Ba(N_3)_2$

Answer 1

Answer: (D)

$Ba(N_3)_2$

Answer 2

$Ba(N_3)_2 \xrightarrow{Heat} Ba(s) + 3N_2 (g )$
Azide salt of barium can be obtained in purest form as well as the decomposition product contain solid Ba as by product along with gaseous nitrogen, hence no additional step of separation is required. Other reactions are
$NH_4 NO_3 \xrightarrow{Heat} N_2 O+2H_2 O$
$2NH_3+3CuO \xrightarrow{Heat} 3Cu+3H_2O+N_2$
$(NH_4)_2 Cr_2 O_7 \xrightarrow{Heat} Cr_2 O_3+4H_2 O+N_2$