Potassium dichromate (K2Cr2O7) and potassium permanganate (KMnO4) give overlapping UV-Vis absorption spectra in 1 M sulphuric acid. K2Cr2O7 shows an absorption maximum at 440 nm and KMnO4 shows the absorption maximum at 545 nm . An unknown sample solution containing a mixture of K2Cr2O7 and KMnO4 was analyzed using a 1-cm cell and the absorbance values at these two wavelengths were as follows:   A440 = 0.515 and A545 = 0.835   The absorbance values for standard solutions of K2Cr2O7 (1.00 x 10-3 M) and KMnO4 (2.00 x 10-4 M) in 1 M sulphuric acid using the same 1 cm cell were as follows:   Calculate the concentrations of K2Cr2O7 and KMnO4 in the unknown sample.

Principles of Instrumental Analysis
7th Edition
ISBN:9781305577213
Author:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Publisher:Douglas A. Skoog, F. James Holler, Stanley R. Crouch
Chapter19: Nuclear Magnetic Resonance Spectroscopy
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Potassium dichromate (K2Cr2O7) and potassium permanganate (KMnO4) give overlapping UV-Vis absorption spectra in 1 M sulphuric acid. K2Cr2O7 shows an absorption maximum at 440 nm and KMnO4 shows the absorption maximum at 545 nm . An unknown sample solution containing a mixture of K2Cr2O7 and KMnO4 was analyzed using a 1-cm cell and the absorbance values at these two wavelengths were as follows:

 

A440 = 0.515 and A545 = 0.835

 

The absorbance values for standard solutions of K2Cr2O7 (1.00 x 10-3 M) and KMnO4 (2.00 x 10-4 M) in 1 M sulphuric acid using the same 1 cm cell were as follows:

 

Calculate the concentrations of K2Cr2O7 and KMnO4 in the unknown sample.

Absorbance, A
Absorbance, A
440 nm
545 m
KCrO,
0.374
0.009
KMnO
0.019
0.475
Transcribed Image Text:Absorbance, A Absorbance, A 440 nm 545 m KCrO, 0.374 0.009 KMnO 0.019 0.475
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