Question

The redox dye DCIP has a molar extinction coefficient of 22,000 at 600 nm.

A. What absorbance would a 5 µM solution have ?

B. A chemical reacts with DCIP to convert it to a colorless, non-absorbing solution. A solution of DCIP with an absorbance of 1.0 is reacted with an aliquot (portion) of this chemical. Afterwards, without volume change, the solution has an absorbance of 0.4. What was the concentration change for DCIP in this reaction (ie how much reacted with the chemical) ?

C. From the answer in question B above, how many moles of DCIP reacted if the total volume of the reaction was 5 mL ?

Answer 1

Acc to Peer -lamberti law, A= Ecl. A = 22000 x 5X10-'x1 = 0.11 B. Abo. af DCIP, A = 1.0 Abs of DCIP fter keaction, A'= 0,4 Cone of Dcie initialya El = 4.54 X10-5M %3D 22000 22000X1 Conc of DCIP after reaction, c' = A' -5 0.4 1.81 ×10 M. 22000x I DCIP = (4.54 -1-81) x 10-5M = 2.73 × 1o -5 M . Cose. eharge f

C. Total volume oL Heaction = 5 mL = 5X10-3L DCIP that keacted = 2,73X10M of no:0f molesleacted of solution n L conc. -2.73X10's volume moles uactd 2.73x10 X5X10 -13.65 x 10 -8 moles. . no. %3D