How does the nitration of phenol with dilute nitric acid differ from nitration of phenol with conc, nitric acid in the presence of sulphuric acid?

Explanation

Phenol react with dilute nitric acid at low temperature (298 K) to give a mixture of a and p nitrophenols

Niration of phenol under drastic conditions give 2,4 , 6, -Trinitrophenol or picric acid .When phenol is nitrated with a mixture of conc `NHO_(3)` in the presence of sulphuric acid , picruc acid is the main product .However , the yield is quite pass due to the oxidation of phenol with conc `HNO_(3)` .