Question

What is the unit of molar absorptivity or absorptivity which is used to determine absorbance A in Beer Lambert’s formula?

(a) L mol^-1 cm^-1

(b) L gm^-1 cm^-1

(c) Cm

(d) No unit

I have been asked this question in my homework.

The doubt is from Introduction to UV Visible Spectrometers in chapter Colorimetry and Spectrometry of Analytical Instrumentation

Answer 1

The correct option is (a) L mol^-1 cm^-1

To explain: The unit of absorptivity is L mol^-1 cm^-1. If concentration is represented as gm per litre it becomes L gm^-1 cm^-1.