Introduction
Benzoic acid is a white crystalline solid and is widely used as a food preservative. It is also used in the production of various products, including pharmaceuticals, dyes, and plastics. The determination of benzoic acid is important in the food industry to ensure that the products are safe for consumption. Titration is a widely used method for determining the concentration of benzoic acid in a sample.
Materials and Methods
To determine the concentration of benzoic acid, we need the following materials: – Benzoic acid sample – Sodium hydroxide solution (0.1 M) – Phenolphthalein indicator – Burette – Conical flask – Distilled water Firstly, weigh accurately about 0.1 g of benzoic acid sample and dissolve it in 50 mL of distilled water in a conical flask. Add 2-3 drops of phenolphthalein indicator to the solution. Next, titrate the solution with 0.1 M sodium hydroxide solution until the pink color of the indicator persists for at least 30 seconds.
Results
The volume of sodium hydroxide solution used for titration is recorded. From the volume of sodium hydroxide solution used, the concentration of benzoic acid in the sample can be calculated using the formula: Concentration of benzoic acid (g/L) = Volume of sodium hydroxide solution (mL) x 0.1 x 12.5 / Weight of benzoic acid sample (g)
Discussion
Titration is a simple and accurate method for determining the concentration of benzoic acid in a sample. The use of phenolphthalein indicator ensures the endpoint of the titration is easily observed. The concentration of benzoic acid in the sample can be calculated from the volume of sodium hydroxide solution used for titration. The result of the determination can be used to ensure the safety of food products.
Precautions
– The benzoic acid sample should be accurately weighed to ensure the accuracy of the result. – The sodium hydroxide solution should be standardized before use. – The titration should be performed in a well-lit environment to ensure accurate observation of the endpoint. – The equipment used for titration should be clean and dry to prevent contamination.
Conclusion
In conclusion, the determination of benzoic acid by titration method is a simple and accurate method. It is widely used in the food industry to ensure the safety of food products. The use of phenolphthalein indicator ensures the endpoint of the titration is easily observed. Precautions should be taken to ensure the accuracy of the result.