$${P_2}{H_4}$$ can be removed from phosphine containing traces of it
A.
by passing impure $$P{H_3}$$ gas through a freezing mixture.
B.
by passing the impure $$P{H_3}$$ gas through $$HI$$ and then its treatment with $$KOH\left( {aq} \right).$$
C.
by both (A) and (B).
D.
by none of these.
Answer :
by both (A) and (B).
Solution :
Both the methods (A) and (B) can be used. When passed through freezing mixture the $${P_2}{H_4}$$ present condenses and pure $$P{H_3}$$ is obtained.
When passed through $$HI,P{H_3}$$ is absorbed forming $$P{H_4}I.P{H_4}I$$ when treated with $$KOH\left( {aq} \right)$$ yields pure phosphine.
$$\eqalign{
& P{H_3} + HI \to P{H_4}I \cr
& P{H_4}I + KOH\left( {aq} \right) \to KI + {H_2}O + P{H_3} \uparrow \cr} $$
Releted MCQ Question on Inorganic Chemistry >> P - Block Elements
Releted Question 1
The reddish brown coloured gas formed when nitric oxide is oxidised by air is