Dear Meh Rdad

Hello

I hope that might help to you.

please find and attached your file.

Best wishes.

Thanks But I am looking for the rate of the reaction

Do you mean azobenzene, or the benzenediazonium ion?

Kinetics of conversion of Diazo-benzene to phenol in water solution is first order reaction

as the rate of the reaction is dependent on the coc. of diazonium ion.

Thank you do you know any paper about that?Can I increase the rate by changing EWG or EDG on ortho or metha position? 

The rate of hydrolysis does not correlate with Hammet σ values (see link), which is not surprising given that the π orbitals are not involved in the reaction.  Dissociation to the phenyl cation can be accelerated by steric crowding at the ortho positions, but I can't think of any meta or para substituents that would have an effect. 

http://pubs.acs.org/doi/abs/10.1021/ja01030a037?journalCode=jacsat

Thank you James