Pre-Assignments

1. Why will the Beer-Lambert law be applicable only for dilute solutions, non-fluorescent substances and for the samples where neither association nor dissociation is present?
2. If Beer-Lambert law is strictly followed by an absorbing substance, what will happen if the path length is doubled and concentration is halved?
3. Will the Beer-Lambert law be applicable to vibrational spectroscopy?
4. What is the origin of the dependence of absorbance on wavelength?
5. For a very dilute solution (small c, concentration), the intensity of absorbed light is given by, I _abs = 2.303 I ₀ ¦Å c l. Verify it. [Hint: I _abs = I ₀ - I _trans ]

Post-Assignments

1. Do you expect a similar fall in absorbance values with the decrease in concentration, if you replace potassium dichromate (K ₂ Cr ₂ O ₇ ) by potassium dichromate solution? Justify your answer.
2. What is the value of the intercept of your calibration plot? Justify your answer.
3. How will a plot of ε versus concentration be different from that of absorbance versus concentration?
4. Plot transmission versus concentration for a given λ (preferably near λ _max ). How is it different from the absorbance vs. concentration plot?