The preparation of 2,4-dinitrophenol from phenol and nitric acid using sulfuric acid as a catalyst involves the nitration of phenol. The balanced chemical equation for this reaction is:C6H5OH phenol + 2 HNO3 nitric acid C6H3 NO2 2OH 2,4-dinitrophenol + 2 H2O water From the balanced equation, we can see that 1 mole of phenol reacts with 2 moles of nitric acid to produce 1 mole of 2,4-dinitrophenol. Therefore, the correct molar ratio of phenol to nitric acid for this reaction is 1:2.