The preparation of 2,4-dinitrobenzoic acid from benzoic acid involves a nitration reaction, which requires a mixture of concentrated nitric acid HNO3 and concentrated sulfuric acid H2SO4 as the nitrating agent. The optimum concentration of nitric acid for this reaction is typically around 60-70% v/v , with sulfuric acid being the remaining 30-40%.The concentration of nitric acid affects the overall yield of the synthesis reaction in several ways:1. Reaction rate: Higher concentrations of nitric acid can increase the reaction rate, leading to a faster formation of the desired product. However, this can also lead to over-nitration and the formation of undesired by-products.2. Selectivity: The concentration of nitric acid can influence the selectivity of the reaction, meaning the formation of the desired 2,4-dinitrobenzoic acid versus other possible nitrobenzoic acid isomers e.g., 2,3-dinitrobenzoic acid or 2,5-dinitrobenzoic acid . A balance must be struck between achieving a high yield of the desired product and minimizing the formation of undesired by-products.3. Safety: Concentrated nitric acid is a strong oxidizing agent and can be hazardous to handle. Using a lower concentration of nitric acid may be safer, but it may also result in a lower yield of the desired product.In summary, the optimum concentration of nitric acid for preparing 2,4-dinitrobenzoic acid from benzoic acid is around 60-70% v/v . This concentration provides a balance between reaction rate, selectivity, and safety, leading to a higher overall yield of the desired product. However, it is essential to carefully control the reaction conditions e.g., temperature, reaction time to minimize the formation of undesired by-products and ensure a high yield of 2,4-dinitrobenzoic acid.