Vitamin C Determination By Iodine Titration Lab Report
Vitamin C, also known as ascorbic acid, is an essential nutrient for human beings. It is a water-soluble vitamin that cannot be synthesized by the body, hence it needs to be obtained through diet or supplements. Vitamin C is vital for maintaining healthy skin, teeth, gums, bones, and cartilage. It also helps in the absorption of iron and is a powerful antioxidant that protects against oxidative stress.
Introduction
In this lab report, we will discuss the determination of Vitamin C by iodine titration. The objective of this experiment is to determine the concentration of Vitamin C in a given sample using iodine solution. Iodine is an oxidizing agent that reacts with Vitamin C and converts it into dehydroascorbic acid. The reaction between iodine and Vitamin C is a redox reaction, and the endpoint is indicated by the color change from brownish-yellow to colorless.
Materials and Methods
The materials used in this experiment are:
- Vitamin C sample
- Iodine solution
- Starch solution
- Sodium thiosulfate solution
- Distilled water
- Burette
- Pipette
- Erlenmeyer flask
- Funnel
- Beaker
- Bunsen burner
- Clamp stand
- White tile
The method used in this experiment is:
- Weigh 0.1 g of Vitamin C sample and dissolve it in 50 ml of distilled water.
- Add 1 ml of starch solution to the Vitamin C solution.
- Titrate the Vitamin C solution with iodine solution until a blue-black color appears.
- Add 1 ml of sodium thiosulfate solution to the iodine solution to decolorize it.
- Repeat the above steps until a constant volume of iodine solution is used.
- Record the volume of iodine solution used in the titration.
Results
The following results were obtained:
- Volume of iodine solution used in titration = 17.5 ml
- Concentration of iodine solution = 0.1 M
- Molar mass of Vitamin C = 176.12 g/mol
Discussion
The concentration of Vitamin C in the given sample can be calculated using the following formula:
Concentration of Vitamin C = (Volume of iodine solution x Concentration of iodine solution x Molar mass of Vitamin C) / Weight of Vitamin C sample
Substituting the values in the above formula, we get:
Concentration of Vitamin C = (17.5 x 0.1 x 176.12) / 0.1 = 30.82 g/L
Hence, the concentration of Vitamin C in the given sample is 30.82 g/L.
Conclusion
The determination of Vitamin C by iodine titration is a simple and reliable method for analyzing the concentration of Vitamin C in a given sample. The method involves the use of iodine solution as an oxidizing agent and starch solution as an indicator. The endpoint is indicated by the color change from brownish-yellow to colorless. The concentration of Vitamin C in the given sample was found to be 30.82 g/L.