Question

why ozone is found above in the atmosphere even after high vapour density in comparison to other gases in that part

Answer 1

Ozone is found in the two layers of atmosphere with a high percentage in stratospheres and the remaining in troposphere. The air in the stratosphere is dry and doesnot consist of water vapours. Vapour density of a gas is the density of vapour in relation to that of hydrogen. High vapour density means that the ozone is found in vapour form but it do not have any effect on the formation of ozone.
An ozone-oxygen cycle takes place up in the stratosphere by which ozone molecules are produced. The reaction taking place is given below ;
$$\begin{gathered} {\mathrm{O}}_2+{\mathrm{h\nu }}_{\mathrm{uv}}\to 2\mathrm{O} \\ \mathrm{O}+{\mathrm{O}}_2\leftrightarrow {\mathrm{O}}_3 \end{gathered}$$
The ultraviolet light strikes the ordinary oxygen molecules which splits into nascent oxygen. This nascent oxygen then combines with the oxygen molecule to form ozone molecule. The ozone molecule is unstable and when ultraviolet light hits ozone it breaks into oxygen molecule and nascent oxygen. This process continues and is called ozone-oxygen cycle.