Define Standard Titration for estimation of reducing sugar by Fehling Soxhlet Method?
Pipette 5 ml of Fehling's A and 5 ml of Fehling B solution into a 100 ml conical flask. Add approximately 8-9 ml standard glucose solution from a burette so that about 40-45 mg of glucose are added to the flask (to reduce 10 ml of Fehling's solution about 50 mg of glucose are required). Heat the flask on wire gauze till it starts boiling. After about 30-40 seconds add 1 ml of 0.2% methylene blue solution. Continue titratation by adding sugar solution from the burette a few drops at a time and try to finish the titration in 1 minute. At the end point the methylene blue turns colourless. The remaining solution is reddish brown. Repeat the titration till concordant values are obtained. Calculate the amount of glucose required to reduce 10 ml of Fehling's solution and standardize the Fehling's solution.