Question

Complete the reaction
$P{H_4}I + NaOH$ :
(A) $P{H_3}$
(B) $N{H_3}$
(C) ${P_4}{O_6}$
(D) ${P_4}{O_{10}}$

Answer 1

This reaction is worth noting because it produces one of the key reactants used in the production of phosphonium iodide. That reactant in combination with hydrogen iodide produces phosphonium iodide. The structure of that reactant is similar to ammonia but is a much poorer solvent and also less soluble in water.

Complete step by step solution
This question is from the compounds and their properties from the p-block. We are asked for the products of a chemical reaction. So first let us look at the reactants we have. The first one is $P{H_4}I$ which is phosphonium iodide. The second one is $NaOH$ which is sodium hydroxide. Phosphonium iodide is produced when impure phosphine is reacted with hydrogen iodide. The reaction for the same is shown below,
$P{H_3} + HI \to P{H_4}I$
Now if phosphonium iodide is reacted with sodium hydroxide it produces phosphine, sodium iodide and water. The reaction is shown below,
$P{H_4}I + NaOH \to P{H_3} + NaI + {H_2}O$
We can see this is an interesting reaction as phosphine which was used to create phosphonium iodide is now created by the reaction of phosphonium iodide and sodium hydroxide. The producer of the reactant is formed as a product. That is why phosphine is notable here. So $P{H_3}$ is our answer.
So option A is the correct answer.

Note
Phosphine is a colorless gas. It is also flammable in nature. It is formed by the reaction of calcium phosphide and water. Its odor resembles garlic or decaying fish. As a fact it is heavier than air. It is used as an insecticide and powder in bags. It is poisonous in nature and smelling it can cause severe health issues. It is also used as a semiconductor industry.