pBlock ElementsII 1 Question 8
8. The compound that does not produce nitrogen gas by the thermal decomposition is
(2018 Main)
(a) $\mathrm{Ba}\left(\mathrm{N}{3}\right){2}$
(c) $\mathrm{NH}{4} \mathrm{NO}{2}$
(b) $\left(\mathrm{NH}{4}\right){2} \mathrm{Cr}{2} \mathrm{O}{7}$
(d) $\left(\mathrm{NH}{4}\right){2} \mathrm{SO}_{4}$
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Solution:
- The thermal decomposition of given compounds is shown below
$$ \begin{gathered} \left(\mathrm{NH}{4}\right){2} \mathrm{Cr}{2} \mathrm{O}{7} \stackrel{\Delta}{\longrightarrow} \mathrm{N}{2}+4 \mathrm{H}{2} \mathrm{O}+\mathrm{Cr}{2} \mathrm{O}{3} \ \mathrm{NH}{4} \mathrm{NO}{2} \stackrel{\Delta}{\longrightarrow} \mathrm{N}{2}+2 \mathrm{H}{2} \mathrm{O} \ \left(\mathrm{NH}{4}\right){2} \mathrm{SO}{4} \stackrel{\Delta}{\longrightarrow} 2 \mathrm{NH}{3}+\mathrm{H}{2} \mathrm{SO}{4} \ \mathrm{Ba}\left(\mathrm{N}{3}\right){2} \longrightarrow \mathrm{Ba}+3 \mathrm{~N}_{2} \end{gathered} $$
Thus, only $\left(\mathrm{NH}{4}\right){2} \mathrm{SO}{4}$ does not gives $\mathrm{N}{2}$ on heating (It give $\mathrm{NH}{3}$ ). While rest of the given compounds gives $\mathrm{N}{2}$ on their thermal decomposition.
