Question

$AsC{l}_3+NaB{H}_4\to P+NaCl+BC{l}_3$
Mark the correct option(s) which is/are true for compound $P$:

• A. It thermally decomposes into a poisonous element and hydrogen
• B. It is $s{p}^3$ hybridised with a bond angle close to that of $N{H}_3$
• C. It readily oxidises in the presence of air
• D. With solid $AgN{O}_3,P$ reacts to produce a yellow compound, $P$ reacts with a solution of $AgN{O}_3$ to give a black compound

Answer 1

Answer: (A), (C), (D)

The correct options are
A It thermally decomposes into a poisonous element and hydrogen
C It readily oxidises in the presence of air
D With solid $AgN{O}_3,P$ reacts to produce a yellow compound, $P$ reacts with a solution of $AgN{O}_3$ to give a black compound

$4AsC{l}_3+3NaB{H}_4⟶4As{H}_3+3NaCl+3BC{l}_3$
a) $As{H}_3⟶3H_2+2As$
We know that $As$ is poisonous.
b) In $As{H}_3$, the bond angle is ${91}^{\circ }$, which suggests that it is not $s{p}^3$ hybridised. This is because elements below the $2^{nd}$ period do not undergo hybridisation with electropositive elements like hydrogen. (Drago's rule).
c) $2As{H}_3+3O_2\to A{s}_2{O}_3+3H_{2}O$
d) With solid $AgN{O}_3,As{H}_3$ reacts to produce yellow $A{g}_{4}AsN{O}_3,$ whereas $As{H}_3$ reacts with a solution of $AgN{O}_3$ to give black $A{g}_{3}As$.