Question

4. The following data was obtained for an ac solution of Picric acid of 9.5 x 10-‐5 M using a uv-vis spectrophotometer and 0.5 cm cells

λ (nm)	330	350	370	390	400	410	430	450
A	0.18	0.28	0.40	0.45	0.52	0.45	0.33	0.12

a) realice graoh of the absorption spectrum of absorptivity molar Coefient (ε) as a function of λ

b) Select the optimal wavelength to take the reading on a calibration curve

Answer 1

Answer:

data is

wavelength Absorbance A/cl 330 0.18 1894.736842 350 0.28 2947.368421 370 0.4 4210.526316 390 0.45 4736.842105 400 0.52 5473.684211 410 0.45 4736.842105 430 0.33 3473.684211 450 0.12 1263.157895

plot is

600 5473.684211 5000 4736.842105 4736.842105 4210.526316 4000 3473.684211 2947.368421 3000 1894.736842 2000 1263.157895 1000 0 320 340 360 380 400 420 440 460

b)

optimal wavelength is 400 nm (where we get maximum absorbance or maximum value for molar absorption)