Question about stability of Ozone

[Kshitij Kabeer]

The enthalpy of formation of O3 is positive. Change in entropy for the formation of O3 is also negative( as the number of gaseous moles is decreasing). This means that Delta G is positive for all temperatures. So formation of ozone should be non spontaneous at all temperatures. Then how does it exist?

 

[Bystander]

Have you looked at the expression for the equilibrium constant?

 

[Kshitij Kabeer]

You mean Delta G=-RTlnK? Yes. So you mean to say that the reaction still occurs but equilibrium favours formation of O2. OK I get your point, So now my question is why do we say the reaction is non spontaneous when Delta G is positive? What is the meaning of spontaneity?

 

[Bystander]

https://en.wikipedia.org/wiki/Spontaneous_process