Question

If the stock iron standard solution was accidentally diluted while handling, would this error cause the reported concentration for the unknown to be high or low? In your explanation, first describe how (1 mark) the slope of the Beer's Law Calibration Graph would be affected.

Answer 1

Let's see ,

Beer's law= if monochromatic light passed through solution , absorbance of monochromatic light increases with increase in concentration.

So , in Beer's law absorbance is directly proportional to concentration of solution .Here as you said ,as you nave diluted iron stock solution by mistake , so absorbance of reference standard solution decreases .

Let's see Beer's equation -

A = m$\LARGE \epsilon$ c

Here ,A = absorbance

m$\LARGE \epsilon$ = molar extinction coefficient

C= concentration moles per liter

The basic idea is to plot graph of concentration Vs absorbance of solution .Once you have that , you can compare absorbance of solution to major concentration of solution by joining two intercepted point of X and Y axis.

But if concentration of standard reference sample went wrong , then whole exercise of determination of unknown concentration will be wrong.

In this regard absorbance of sample gets suppressed to great extent .