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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Answer:
Correct Answer: 45. (b,d)
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.
