I agree with @M.Farooq, IIT JEE is a kind of smudge in the education system that needs to be stained off. No exam will ever want a student to memorise 50-100 without even knowing “where can we find vanadium for making $\ce{V_2O_5}$?”.

I don’t think that we can get phenol from benzene just by $\ce{V_2O_5}$. As you know, $\ce{V_2O_5}$ is an oxidising agent, it will oxidise our benzene.

@KarstenTheis I’m reading Paul’s answer again and again for understanding it properly therefore I’m taking some time.

@Alchimista The Kinectic Energy of cations is the heat ? I mean during their acceleration towards anion they collide with air molecules or beaker and hence we feel the heat, is that it?

@Karl I’m sorry but I’m unable to see What you are pointing out.

I request you to please read my question.