Answer to Question #207565 in Chemistry for Khorshed

Question

Describe Beer-Lambert's law and its limitations.

Answer 1

Beer's law (sometimes called the Beer-Lambert law) states that the absorbance is proportional to the path length, b, through the sample and the concentration of the absorbing species, c: A α b · c. The proportionality constant is sometimes given the symbol a, giving Beer's law an alphabetic look: A = a · b · c.

The linearity of the Beer-Lambert law is limited by chemical and instrumental factors. Causes of nonlinearity include: deviations in absorptivity coefficients at high concentrations (>0.01M) due to electrostatic interactions between molecules in close proximity.