Explain Procedure for Estimation of Sucrose by Fehling Soxhlet Method?
Follow the proceedure enumerated herewith and carry out the experiment:
1. Standard titration (Standardization of Fehling's solution) - Titrate 10 ml of Fehling's solution (5 ml each of Fehling A and B solutions) against standard glucose solution as described in experiment 5. From this titration calculate the amount of glucose required to reduce 10 ml of Fehling's solution.
2. Sample titration - Take the given sample of sucrose solution in 250 ml conical flask. Add 2 ml of Conc HCL and 20-30 ml of distilled water (distilled water is added to prevent charring of the sugar). Heat the flask in a boiling water bath for 20-25 minutes. Remove from the water bath and cool the flask under the tap. Neutralize the acid present in the hydrolyzed solution by adding small amounts (a small pinch at a time) of solid sodium carbonate to the flask until you see no more effervescence in the flask.
Carefully transfer all the contents of this hydrolysis flask to a 100 ml volumetric flask. Ensure that the hydrolysis flask is rinsed with a little (5-10 ml) distilled water 3-4 times and the rinsings are transferred to the volumetric flask. Make up the volume to the 100 ml mark with distilled water. Shake well and use this solution in the burette. Now, take 5 ml of Fehling A and 5 ml of Fehling B in a 100 ml conical flask. Titrate the dilute hydrolyzed sugar solution with Fehling's solution using Fehling Soxhlet increment method.