Question

Dehydrated phosphorus trichloride in water gives:
A. ${{H}_{3}}P{{O}_{3}}$
B. ${{H}_{3}}P{{O}_{4}}$
C. ${{H}_{3}}P{{O}_{2}}$
D. None

Answer 1

Hint: Phosphorus trichloride is the colourless fuming liquid which is used in the textile finishing and gasoline additives. It is a covalent molecule. Phosphorus trichloride is toxic and volatile in nature.

Complete step by step answer:
Phosphorus trichloride is defined as a compound that contains phosphorus and chlorine, and has a chemical formula, $PC{{l}_{3}}$ . When it is reacted with water, it produces $HCl$ gas. It is a toxic and volatile liquid which reacts with water violently. It contains lone pairs in the phosphorus atom and gives trigonal pyramidal shape. It has various uses; it is used in the manufacture of phosphites and organophosphorus compounds. In phosphorus trichloride, phosphorus has $+3$ oxidation state.
When phosphorus trichloride reacts with water, it gives ${{H}_{3}}P{{O}_{3}}$ as a product.
The reaction of the same can be given as follows:
$3{{H}_{2}}O+PC{{l}_{3}}\to {{H}_{3}}P{{O}_{3}}+3HCl$
The product formed is phosphorous acid, which is diprotic in nature, that means it readily ionizes two protons. It is used in the production of basic lead phosphites which is a stabilizer in PVC (Polyvinyl chloride).

So, the correct answer is “Option A”.

Note: Here, the phosphorus chloride shows trigonal pyramidal shape. It is a molecular shape, which is formed when there are three bonds and one lone pair on the central atom. Here, the central phosphorus atom is $s{{p}^{3}}$ hybridized and has three bond pairs and one lone pair
The product formed is phosphorus acid $({{H}_{3}}P{{O}_{3}})$ which is diprotic in nature.
The phosphorus trichloride reaction with water is toxic.
In solid state, ${{H}_{3}}P{{O}_{3}}$ is tetrahedral in shape.