Q54 / 200 · Manipal (MET) 2014 · Chemistry
Out of the following redox reactions
I. $\mathrm{NH}_4 \mathrm{NO}_3 \xrightarrow{\Delta} \mathrm{~N}_2 \mathrm{O}+2 \mathrm{H}_2 \mathrm{O}$
II. $\mathrm{NH}_4 \mathrm{NO}_2 \xrightarrow{\Delta} \mathrm{~N}_2+2 \mathrm{H}_2 \mathrm{O}$
III. $\mathrm{PCl}_5 \xrightarrow{\Delta} \mathrm{PCl}_3+\mathrm{Cl}_2$
disproportionation is not shown in
- AI and II
- BII and III
- CI and III
- Correct answerDI, II and III
Solution
$\text { I. } \mathrm{NH}_{-3}^{+} \mathrm{NO}_3^{-} \longrightarrow \underset{+1}{\mathrm{~N}_2 \mathrm{O}+2 \mathrm{H}_2 \mathrm{O}}$
It is a redox reaction but not a disproportionation reaction. Since, different N -species are involved. II. $\mathrm{NH}_{-3}^{+}{ }_{+3}^{+} \mathrm{NO}_2{ }^{-} \longrightarrow \underset{0}{\mathrm{~N}_2}$ same as (I) III. $\mathrm{PCl}_5 \longrightarrow \mathrm{PCl}_3 \longrightarrow+\underset{+3-1}{\mathrm{Cl}_2}$
Thus, it is also not a disproportionation reaction.
It is a redox reaction but not a disproportionation reaction. Since, different N -species are involved. II. $\mathrm{NH}_{-3}^{+}{ }_{+3}^{+} \mathrm{NO}_2{ }^{-} \longrightarrow \underset{0}{\mathrm{~N}_2}$ same as (I) III. $\mathrm{PCl}_5 \longrightarrow \mathrm{PCl}_3 \longrightarrow+\underset{+3-1}{\mathrm{Cl}_2}$
Thus, it is also not a disproportionation reaction.
Hence, the correct answer is option: 'D'.