pBlock ElementsII - Result Question 11
####11. The pair in which phosphorus atoms have a formal oxidation state of +3 is
(2016 Main)
(a) pyrophosphorous and hypophosphoric acids
(b) orthophosphorous and hypophosphoric acids
(c) pyrophosphorous and pyrophosphoric acids
(d) orthophosphorous and pyrophosphorous acids
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Solution:
- Orthophosphorous acid, $H _3 PO _3: HO-{ } _P^{P}-OH$
$H _3 PO _3=3+x+3(-2)=0$ or $x=+3$
Pyrophosphorous acid, $H _4 P _2 O _5$ :
$H _4 \stackrel{x}{P} O _5=4+2 x+5(-2)=0$
$4+2 x-10=0, x=+3$
