JEE Advanced 2021Paper 2

Exam: JEE Advanced
Year: 2021
Paper: Paper 2
Subject: Chemistry
Chapter: p Block Elements (Group 15, 16, 17 & 18)

JEE Advanced 2021 · Paper 2 · Chemistry · p Block Elements (Group 15, 16, 17 & 18)

The correct statement(s) related to oxoacids of phosphorous is(are)

Options

AUpon heating, ${H}_{3}{PO}_{3}$ undergoes disproportionation reaction to produce ${H}_{3}{PO}_{4}$ and ${PH}_{3}$ .
BWhile ${H}_{3}{PO}_{3}$ can act as reducing agent, ${H}_{3}{PO}_{4}$ cannot.
C ${H}_{3}{PO}_{3}$ is a monobasic acid.
DThe $H$ atom of $P - H$ bond in ${H}_{3}{PO}_{3}$ is not ionizable in water.

Correct answer

A. Upon heating, ${H}_{3}{PO}_{3}$ undergoes disproportionation reaction to produce ${H}_{3}{PO}_{4}$ and ${PH}_{3}$ .

Step-by-step solution

$4{H}_{3}{PO}_{3}\overset{∆}{\to}$ $3{H}_{3}{PO}_{4} + {PH}_{3}$ (Disproportionation)

Oxidation state of $' P '$ in ${H}_{3}{PO}_{4}$ is $+ 5$ which is maximum oxidation state of $' P '$ so ${H}_{3}{PO}_{4}$ cannot act as a reducing agent whereas ${H}_{3}{PO}_{3}$ can act as a reducing agent because the oxidation state is $+ 3$ and it can increase upto $+ 5$ .

$⇒$ ${H}_{3}{PO}_{3}$ :

The correct statement(s) related to oxoacids of phosphorous is(are)

It is dibasic acid.

$⇒$ Only $H$ - atom attached with $' O '$ is ionizable.

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