The preparation of 2,4-dinitrobenzoic acid from benzoic acid and nitric acid can be done through a nitration reaction. Here is a step-by-step procedure:1. Safety precautions: Wear appropriate personal protective equipment PPE such as gloves, goggles, and a lab coat. Perform the reaction in a well-ventilated area or a fume hood, as nitric acid is corrosive and toxic.2. In a round-bottom flask, dissolve an appropriate amount of benzoic acid e.g., 5 g in a solvent like glacial acetic acid e.g., 25 mL . The solvent should be anhydrous and non-reactive with nitric acid.3. Cool the reaction mixture in an ice bath to minimize the risk of side reactions and over-nitration.4. Slowly add concentrated nitric acid e.g., 5 mL to the reaction mixture while stirring. The addition should be done dropwise and over a period of 30-60 minutes to ensure controlled nitration.5. After the addition of nitric acid is complete, continue stirring the reaction mixture in the ice bath for an additional 30 minutes.6. Remove the reaction mixture from the ice bath and let it warm to room temperature. Stir for another 1-2 hours to ensure the completion of the reaction.7. Pour the reaction mixture into a beaker containing crushed ice and water e.g., 50 mL to precipitate the 2,4-dinitrobenzoic acid.8. Filter the precipitate using vacuum filtration and wash it with cold water to remove any remaining impurities.9. Dry the product under vacuum or air-dry it in a desiccator.10. Recrystallize the product from a suitable solvent e.g., ethanol to obtain pure 2,4-dinitrobenzoic acid crystals.To determine the purity of the final product, you can use the following techniques:1. Melting point determination: Determine the melting point of the synthesized 2,4-dinitrobenzoic acid using a melting point apparatus. Compare the obtained value with the literature value approx. 241-243C . A pure compound will have a sharp melting point close to the literature value.2. Thin Layer Chromatography TLC analysis: Prepare a TLC plate and spot the synthesized 2,4-dinitrobenzoic acid along with a reference standard of pure 2,4-dinitrobenzoic acid. Develop the TLC plate using an appropriate solvent system e.g., ethyl acetate:hexane . Visualize the spots under UV light or by staining with a suitable reagent e.g., iodine . Compare the Rf values retention factor of the synthesized compound and the reference standard. If the Rf values match and there is only one spot for each sample, it indicates that the synthesized compound is pure.