Question

Which of the following is true for following compounds:
$H_{3}P{O}_5,H_2{P}_2{O}_6$.

• A. $H_{3}P{O}_5$ contains a peroxy linkage.
• B. $H_2{P}_2{O}_6$ contains a peroxy linkage.
• C. both a and b
• D. None of these

Answer 1

The correct option is A $H_{3}P{O}_5$ contains a peroxy linkage.

The compound contains a peroxy linkage when:
Calculated oxidation state is more the maximum oxidation state possible.

First compound,
$H_{3}P{O}_5$
Let oxidation state of $P$ be $x$.
$\Rightarrow x+3\times (+1)+5\times (-2)=0$
$\Rightarrow x=+7$
calcualted O.S.$=+7$.
while maximum O.S. possible for $P$ is +5. So, $H_{3}P{O}_5$ contains a peroxy linkage.
The structure of $H_{3}P{O}_5$,



Second compound,
$H_4{P}_2{O}_6$
Let oxidation state of Sulphur be $x$.
$\Rightarrow 2x+4\times (+1)+6\times (-2)=0$
$\Rightarrow x=+4$
calcualted O.S.$=+4$.
while maximum O.S. possible for $P$ is +5 so, $H_4{P}_2{O}_6$ does not contains a peroxy linkage.
The structure of $H_4{P}_2{O}_6$,