Question

Why should the y-intercept of any Beer's Law Plot equal zero? Consider the experimental set-up and answer from a conceptual perspective

Answer 1

Answer:

Answer has been given below.

Explanation:

• According to Beer's law-    $A=\epsilon .c.l$
• $\epsilon$ represents molar absorptivity of a solution, c represents molarity of solution and l represents cell thickness.
• Measurement of absorption is done by taking solutions of a particular solute with different concentrations. A particular solute has a particular maximum absorption wavelength. So absorption experiment is done by keeping this maximum absorption wavelength constant.
• $\epsilon$ remains constant for a particular solute and a particular    absorption wavelength.
• During absorption experiment, same cuvette with a particular cell thickness is used. So "l" remains constant during experiment.
• So the variables are "c" and "A" as absorption depends on concentration of solution.
• Therefore Beer's law can be considered as  y=mx relation, where y is equivalent to "A" , x is equivalent to "c" and m is equivalent to "$\epsilon .l$".
• Now, y=mx represents a straight line passing through origin. Therefore  y-intercept of any Beer's law plot equal to zero.