THE PREPARATION OF COPPER(I)OXIDE FEHLING’S TEST



Lab equipment used in the experiment:
Test tube, lab burner, spatula, wash bottle, graduated cylinder

Materials used in the experiment:
Fehling’s solution 1 and 2, glucose

PROCEDURE:
Just before use, mix 5ml of Fehling’s solution 1 and 5 ml of Fehling’s solution 2.
Add 0.2 mg of glucose and boil.

Fehling’s test is based on the reducing property of monosaccharides and disaccharides. This test is performed by adding sugar solution to a mixture of Fehling 1- CuSO4 and Fehling 2 – KOH and Na-K-tartarate. When an alkaline solution of cupric hydroxide is heated in the presence of a reducing sugar, it gets reduced from blue mixture to insoluble yellow or red colored cuprous oxide.

Conclusion:
The appearance of a brownish red precipate indicates the presence of reducing sugars in the sample.
The chemistry involved in Fehling’s test is as follows:
CuSO4+2KOH→CuOH2 + K2SO4
CuOH2→CuO+H2O
Glucose+2CuO→gluconic acid+Cu2O

Student A – the one in the video: Karlo Belak
Student B – the one who filmed the experiment: Marko Babić
Student C – the one who uploaded the video: Iva Andrić
Student D – the one who wrote description: Katarina Ćibarić
Student E – the one who edited the video: Mihovil Medić

Experiment was made by students attending Advanced English at Faculty of Chemical Engineering and Technology, University of Zagreb. Lecturer is Nadja Dešpalj.


Post time: Oct-09-2017