Question

The reaction of \[{P_4}\] with aqueous $NaOH$ gives:
A. $P{\left( {OH} \right)_3}$
B. ${P_2}{O_5}$
C. $P{\left( {OH} \right)_5}$
D. $P{H_3}$

Answer 1

Hint: Aqueous $NaOH$ acts as the reactant here, which proves the presence of water molecules as part of the reactant mixture.
Elemental Phosphorus: The elemental phosphorus which is also known as white phosphorus is a waxy solid, which readily reacts with oxygen when exposed to air. The molecules of white phosphorus exist as four atoms of the element bound together.

Complete step by step answer:
The reaction is highly exothermic as at a high temperature the phosphorus catches fire when reacting with oxygen. This phosphorus is also observed in different water bodies, where the reaction is slower. The product of reaction in air is less toxic as compared to the aquatic environment. The reaction produces phosphine in water which is a highly toxic chemical.
Phosphine is a colourless and flammable gas which is highly toxic. This is naturally produced in the aquatic environment which later evaporates out of the water. This is industrially prepared using the same chemical process as given here. Even though the phosphine is toxic in nature the gas is used for the purpose of fumigation and in the preparation of semiconductors.
The reaction that takes place between \[{P_4}\] and aqueous $NaOH$ leads to the generation of phosphine $\left( {P{H_3}} \right)$ as a product. The reaction proceeds according to the given chemical equation:
${P_4} + NaOH + {H_2}O \to P{H_3} + Na{H_2}P{O_2}$
The balanced chemical equation for the process,
${P_4} + 3NaOH + 3{H_2}O \to P{H_3} + 3Na{H_2}P{O_2}$
In this process the reaction occurs at a slower rate as the cold solution of $NaOH$ is used for the reaction. In the presence of water, the elemental phosphorus reacts with sodium hydroxide producing phosphine. This is a process used in industrial production of phosphine.

So, the correct answer is Option D.

Note: Environment with water is required for the process to take place and hence aqueous environment is important for the reaction. The reaction of concentrated sodium hydroxide with elemental phosphorus brings forth different results.