Question

${\mathrm{PCl}}_3$ on hydrolysis gives fumes of -

• A. ${\mathrm{H}}_3{\mathrm{PO}}_3+\mathrm{HCl}$
• B. ${\mathrm{H}}_3{\mathrm{PO}}_4+\mathrm{HCI}$
• C. ${\mathrm{H}}_3{\mathrm{PO}}_2\mathrm{and}{\mathrm{H}}_3{\mathrm{PO}}_3$
• D. ${\mathrm{H}}_3{\mathrm{PO}}_2+\mathrm{HCl}$

Answer 1

The correct option is A

${\mathrm{H}}_3{\mathrm{PO}}_3+\mathrm{HCl}$

Explanation for the correct option:

Option (A):${\mathrm{H}}_3{\mathrm{PO}}_3+\mathrm{HCl}$

• A hydrolysis reaction is known as any chemical reaction in which a molecule of water reacts with other molecules to form their respective acids, hence it is the opposite of a condensation reaction.
• Phosphorus trichloride (${\mathrm{PCl}}_3$) undergoes the reaction with water forming Ortho phosphorous acid, along with the formation of Hydrochloric acid.
• The chemical equation for the above hydrolysis reaction can be given as :

$\underset{(\mathrm{Phosphorus}\mathrm{trichloride})}{{\mathrm{PCl}}_3\left(\mathrm{l}\right)}+\underset{\left(\mathrm{water}\right)}{3{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right)}\to \underset{\left(\mathrm{Ortho}\mathrm{phosphorous}\mathrm{acid}\right)}{{\mathrm{H}}_3{\mathrm{PO}}_3\left(\mathrm{s}\right)}+\underset{\left(\mathrm{Hydrochloric}\mathrm{acid}\right)}{3\mathrm{HCl}\left(\mathrm{g}\right)}$

Explanation for the incorrect option:

Option (B):${\mathrm{H}}_3{\mathrm{PO}}_4+\mathrm{HCI}$

• ${\mathrm{PCl}}_3$ on hydrolysis does not produce the fumes of ${\mathrm{H}}_3{\mathrm{PO}}_4\mathrm{and}\mathrm{HCI}$.
• Hence, the given option is the incorrect one.

Option (C):${\mathrm{H}}_3{\mathrm{PO}}_2\mathrm{and}{\mathrm{H}}_3{\mathrm{PO}}_3$

• ${\mathrm{H}}_3{\mathrm{PO}}_2\mathrm{and}{\mathrm{H}}_3{\mathrm{PO}}_3$are not the fumes produce on hydrolysis of ${\mathrm{PCl}}_3$.
• Thus, the given option does not coincide with the given concept.

Option (D):${\mathrm{H}}_3{\mathrm{PO}}_2+\mathrm{HCl}$

• ${\mathrm{PCl}}_3$ on hydrolysis does not produce the fumes of ${\mathrm{H}}_3{\mathrm{PO}}_2\mathrm{and}\mathrm{HCl}.$.
• Hence, the given option does not represent the correct concept.

Hence,${\mathrm{PCl}}_3$ on hydrolysis gives fumes of ${\mathrm{H}}_3{\mathrm{PO}}_3+\mathrm{HCl}.$