The preparation of 2,4-dinitrobenzoic acid from benzoic acid and nitric acid involves a nitration reaction. The specific mechanism and reaction conditions are as follows:1. Reaction conditions:- Concentrated nitric acid HNO3 - Concentrated sulfuric acid H2SO4 as a catalyst- Temperature: 0-5C ice bath for the first nitration step, and around 50-60C for the second nitration step2. Mechanism:a Formation of the nitronium ion NO2+ :Concentrated H2SO4 protonates HNO3, forming the nitronium ion NO2+ and bisulfate ion HSO4- .HNO3 + H2SO4 -> NO2+ + HSO4- + H2Ob First nitration step formation of 4-nitrobenzoic acid :The nitronium ion NO2+ acts as an electrophile and attacks the aromatic ring of benzoic acid, forming an intermediate arenium ion. The most favorable position for the first nitration is the para position 4-position due to the electron-withdrawing nature of the carboxyl group -COOH in benzoic acid. The intermediate then loses a proton to regenerate the aromatic ring, resulting in the formation of 4-nitrobenzoic acid.c Second nitration step formation of 2,4-dinitrobenzoic acid :The 4-nitrobenzoic acid undergoes a second nitration reaction, with the nitronium ion attacking the ortho position 2-position relative to the carboxyl group. This forms an intermediate arenium ion, which then loses a proton to regenerate the aromatic ring, resulting in the formation of 2,4-dinitrobenzoic acid.3. Intermediate products:- 4-nitrobenzoic acid- Arenium ion intermediates during the nitration stepsOverall, the reaction can be summarized as:C6H5COOH benzoic acid + 2 HNO3 nitric acid -> C6H3 NO2 2COOH 2,4-dinitrobenzoic acid + 2 H2O water