Question

Why is ozone thermodynamically unstable?

Answer 1

Here the $∆$G (gibb's free energy ) is the determining factor. The chemical species with +$∆$G is considered to be thermodynamically unstable with respect to its element and they have spontaneous tendency to decompose to its constituent elements. For Ozone $∆$G for formation is +163 KJ/mol have tendency to spontaneous decomposition at 25$°$ C and is thermodynamically unstable.The equilibrium constant for formation of ozone is less than one.But it survives because the reaction of decomposition of ozone to O₂ is very slow.
O₃ $\stackrel{}{\to }$ O₂ + O