Question

Calcium imide on hydrolysis gives gas (P) which on oxidation by bleaching powder gives gas (Q), Gas (Q)on reaction with magnesium gives compound (R) which on hydrolysis again gives gas (P), Identify (P), (Q), and (R) :

• A. $N_2,N{H}_3,MgNH$
• B. $N{H}_3,N_2,M{g}_3{N}_2$
• C. $N{H}_3,N{O}_2,Mg(N{O}_2{)}_2$
• D. $N_2,N_2{O}_5,Mg(N{O}_3{)}_2$

Answer 1

Answer: (B)

$N{H}_3,N_2,M{g}_3{N}_2$

Calcium imide on hydrolysis gives gas $N{H}_3$ and $Ca(OH{)}_2$. So $p$ is $N{H}_3$.
$CaNH+2H_{2}O\to N{H}_3+Ca(OH{)}_2$
$N{H}_3$ on oxidation by bleaching powder gives gas $N_2$ and byproducts. So $Q$ is $N_2$
$3CaOC{l}_2+2N{H}_3\to 3CaC{l}_2+3H_{2}O+N_2$
$N_2$ on reaction with magnesium gives compound $M{g}_3{N}_2$
$N_2+3Mg\to M{g}_3{N}_2$.
$M{g}_3{N}_2$ on hydrolysis gives $N{H}_3$, which is nothing but $p$.
$M{g}_3{N}_2+6H_{2}O\to 3Mg(OH{)}_2+2N{H}_3$
So $P,Q,R$ are $N{H}_3,N_2,M{g}_3{N}_2$.
Hence option B is correct.