pBlock ElementsII 1 Question 45
45. The nitrogen containing compound produced in the reaction of $\mathrm{HNO}{3}$ with $\mathrm{P}{4} \mathrm{O}_{10}$
(2016 Adv.)
(a) can also be prepared by reaction of $\mathrm{P}{4}$ and $\mathrm{HNO}{3}$
(b) is diamagnetic
(c) contains one $\mathrm{N}-\mathrm{N}$ bond
(d) reacts with $\mathrm{Na}$ metal producing a brown gas
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Solution:
- $\mathrm{P}{4} \mathrm{O}{10}$ is a dehydrating agent and converts $\mathrm{HNO}{3}$ into $\mathrm{N}{2} \mathrm{O}_{5}$
$$ \begin{aligned} 2 \mathrm{HNO}{3} & \longrightarrow \mathrm{N}{2} \mathrm{O}{5}+\mathrm{H}{2} \mathrm{O} \ \mathrm{P}{4} \mathrm{O}{10}+6 \mathrm{H}{2} \mathrm{O} & \longrightarrow 4 \mathrm{H}{3} \mathrm{PO}_{4} \end{aligned} $$
(a) $\mathrm{P}{4}+20 \mathrm{HNO}{3} \longrightarrow 4 \mathrm{H}{3} \mathrm{PO}{4}+20 \mathrm{NO}{2}+4 \mathrm{H}{2} \mathrm{O}$
Thus, (a) is incorrect. (b) $\mathrm{N}{2} \mathrm{O}{5}$ has no unpaired electron and is thus, diamagnetic thus, (b) is correct.
(c)
There is no $\mathrm{N}-\mathrm{N}$ bond, thus, (c) is incorrect.
(d) $\mathrm{N}{2} \mathrm{O}{5}+\mathrm{Na} \longrightarrow \mathrm{NaNO}{3}+\mathrm{NO}{2}$ $\mathrm{N}{2} \mathrm{O}{5}$ vapours are of brownish colour. Thus, (d) is correct.
