Estimating glucose concentration in solution
Done by : Hasan Al-jowder 11E KC
The purple pink solution of potassium permanganate (MnO4 -) is reduced by glucose to a colourless solution of manganese ions (Mn2+). MnO4- + 8H+ + 5e- Mn2+ + 4H2O
The time taken for the loss of colour from a standardised solution of permanganate is directly related to the concentration of glucose present in solution.
How does the different concentration of glucose solution which have the same volume affects the time taken for the pink color of the potassium permanganate to turn into colorless?
The higher the concentration of glucose, the shorter time taken for the reduction of potassium permanganate, hence resulting in shorter time taken for the pink color of potassium permanganate to decolorize. This is because the concentration of glucose molecules in glucose solution is high thus more electron are donated to the permanganate within a constant period.
•Independent: The concentration of the glucose solution
•Dependent: The time taken for the pink color of the potassium permanganate to turn into colorless •Controlled: Volume/Units
Materials list :
•a glass rod
•a boiling tube and a rack
•glucose solutions (2%,4%,6%,8%,10%,12%)
•3 solution of unknown glucose concentration (A,B,C)
1.label your three beakers sulphuric acid
PP- for potassium permanganate
G- for glucose
2.label your syringes in the same way.
3.add about 25 cm3 of sulphuric acid and potassium permanganate to the beakers - this will be your stock to use throughout the experiment. note which glucose solution you are testing first. 4.use the correct syringe to place 10 cm3 of the first glucose solution into the boiling tube. 5.add 5 cm3 of sulphuric acid.