The preparation of 2,4-dinitrobenzoic acid from benzoic acid involves a nitration reaction using a nitrating mixture of concentrated nitric acid and concentrated sulfuric acid. Here is the step-by-step procedure:Required equipment:1. Round-bottom flask2. Reflux condenser3. Magnetic stirrer and stir bar4. Ice bath5. Separatory funnel6. Vacuum filtration apparatus7. Beakers and glassware8. pH paper or pH meter9. Gloves, goggles, and lab coat for safetyRequired reagents:1. Benzoic acid2. Concentrated nitric acid HNO 3. Concentrated sulfuric acid HSO 4. Sodium bicarbonate NaHCO 5. Distilled water6. Ethanol or acetone for recrystallization Procedure:1. Set up a round-bottom flask with a magnetic stirrer and stir bar. Place the flask in an ice bath to cool it down.2. Weigh out the appropriate amount of benzoic acid 1 equivalent and add it to the flask.3. Prepare the nitrating mixture by slowly adding concentrated nitric acid 2.2 equivalents to concentrated sulfuric acid 2.2 equivalents in a separate container. Always add the nitric acid to the sulfuric acid, not the other way around. This mixture should be prepared in an ice bath to control the temperature.4. Slowly add the nitrating mixture to the round-bottom flask containing benzoic acid, while stirring and maintaining the ice bath. The addition should be done dropwise to control the exothermic reaction.5. Once the nitrating mixture has been added, set up a reflux condenser on the round-bottom flask and heat the reaction mixture to 50-60C. Maintain this temperature for 2-3 hours to ensure complete nitration.6. After the reaction is complete, carefully pour the reaction mixture into a large volume of ice-cold water to quench the reaction and precipitate the product. Stir the mixture to facilitate precipitation.7. Filter the precipitate using a vacuum filtration apparatus and wash the solid with cold distilled water to remove any remaining acid.8. To further purify the product, dissolve the crude 2,4-dinitrobenzoic acid in a minimal amount of hot ethanol or acetone. Allow the solution to cool slowly to room temperature and then place it in an ice bath to induce recrystallization. Filter the recrystallized product using vacuum filtration.9. To neutralize any residual acid, wash the recrystallized product with a cold, dilute solution of sodium bicarbonate NaHCO until the pH of the filtrate is neutral as indicated by pH paper or a pH meter .10. Dry the purified 2,4-dinitrobenzoic acid under vacuum or in a desiccator.Expected yield and purity:The yield of 2,4-dinitrobenzoic acid from this procedure can vary depending on the efficiency of the nitration reaction and the purification steps. However, a typical yield for this reaction is around 60-70%. The purity of the product can be determined by melting point analysis, thin-layer chromatography TLC , or nuclear magnetic resonance NMR spectroscopy. A high-purity product should have a melting point close to the literature value of 241-243C.