Write a balanced chemical equation for the reaction showing catalytic oxidation of $\mathrm{NH}_3$ by atmospheric oxygen.
Ammonia $\left(\mathrm{NH}_3\right)$ on catalytic oxidation by atmospheric oxygen in presence of $\mathrm{Rh} / \mathrm{Pt}$ gauge at 500 K under pressure of 9 bar produces nitrous oxide.
Balanced chemical reaction can be written as
$4 \mathrm{NH}_3+\underset{\text { From air }}{5 \mathrm{O}_2}\xrightarrow[500 \mathrm{~K} ; 9 \mathrm{bar}]{\mathrm{Pt} / \text { Rh gauge catalyst }}4 \mathrm{NO}+6 \mathrm{H}_2 \mathrm{O}$
Write the structure of pyrophosphoric acid.
Molecular formula of pyrophosphoric acid is $\mathrm{H}_4 \mathrm{P}_2 \mathrm{O}_7$ and its structure is as follows
$\mathrm{PH}_3$ forms bubbles when passed slowly in water but $\mathrm{NH}_3$ dissolves. Explain why?
Dissolution of $\mathrm{NH}_3$ and $\mathrm{PH}_3$ in water can be explained on the basis of H -bonding. $\mathrm{NH}_3$ forms H -bond with water so it is soluble but $\mathrm{PH}_3$ does not form H -bond with water so it remains as gas and forms bubble in water.
In $\mathrm{PCl}_5$, phosphorus is in $\mathrm{sp}^3 \mathrm{d}$ hybridised state but all its five bonds are not equivalent. Justify your answer with reason.
It has trigonal bipyramidal geometry, in which two Cl atoms occupy axial position while three occupy equatorial positions. All five $\mathrm{P}-\mathrm{Cl}$ bonds are not identical. There are two types of bond lengths (i) Axial bond lengths (ii) Equatorial bond lengths
Thus, difference in bond length is due to fact that axial bond pairs suffer more repulsion as compared to equatorial bond pairs.
Why is nitric oxide paramagnetic in gaseous state but the solid obtained on cooling it is diamagnetic?
In gaseous state, $\mathrm{NO}_2$ exists as a monomer which has one unpaired electron but in solid state, it dimerises to $\mathrm{N}_2 \mathrm{O}_4$ so no unpaired electron left. Therefore, $\mathrm{NO}_2$ is paramagnetic in gaseous state but diamagnetic in solid state.
