Verify the Beer Lambert law for KMnO4 and determine concentration of the given solution of the substance from absorption measurement
Answers
1) Beer-Lambert's law states that absorption of solution is light by the solution is directly proportional to it's path-length and concentration.
2) Mathematically, it is expressed as A = ∈bc.
where, A = absorbance
∈ = molar extinction coefficient
b = path length
c = concentration
3) It is possible to determine the concentration of unknown sample solution (in present case KMnO4) using calibration curve method.
4) In calibration curve method, series of standard solutions of known concentration is prepared. Absorbance of each of the solution is monitored with the help of spectro-photometer.
5) A graph of absorbance Vs concentration is prepared (as shown in figure below).
6) Finally, solution of unknown concentration is introduced in the path of light and it's absorbance is recorded.
7) From the calibration curve and absorbance of unknown sample solution of KMnO4, it is possible to determine the concentration of unknown sample solution.
