pBlock ElementsII - Result Question 157
####45. The nitrogen containing compound produced in the reaction of $HNO _3$ with $P _4 O _{10}$
(2016 Adv.)
(a) can also be prepared by reaction of $P _4$ and $HNO _3$
(b) is diamagnetic
(c) contains one $N-N$ bond
(d) reacts with $Na$ metal producing a brown gas
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Solution:
- $P _4 O _{10}$ is a dehydrating agent and converts $HNO _3$ into $N _2 O _5$
$$ \begin{aligned} 2 HNO _3 & \longrightarrow N _2 O _5+H _2 O \ P _4 O _{10}+6 H _2 O & \longrightarrow 4 H _3 PO _4 \end{aligned} $$
(a) $P _4+20 HNO _3 \longrightarrow 4 H _3 PO _4+20 NO _2+4 H _2 O$
Thus, (a) is incorrect. (b) $N _2 O _5$ has no unpaired electron and is thus, diamagnetic thus, (b) is correct.
(c)
There is no $N-N$ bond, thus, (c) is incorrect.
(d) $N _2 O _5+Na \longrightarrow NaNO _3+NO _2$ $N _2 O _5$ vapours are of brownish colour. Thus, (d) is correct.
