4.00 mL of potassium ferricyanide is put into each flask (1-4) . In Flask 2 add 1.00 mL of glucose stock (2.78x10^-3 M), add 2.00 mL into Flask 3, 3.00 mL into Flask 4, and in Flask U add 1.00 mL of glucose stock. Determine glucose concentration in each stock solution.