Beers Law : Serial Dilution of Potassiun Permangabate using UV-Vis Spectroscopy

Question

Beers Law : Serial Dilution of Potassiun Permangabate using UV-Vis Spectroscopy
Has anyone done this lab and understand how to get the proper values?
neter100 M Kuro. (1580 g/L solution) 3 100-ml volumetric flasks 1 s0-ml volumetric flask 1 25-ml volumetric flask 150-ml beaker (for waste) 100-ml beaker 2 5-ml volumetric pipets (or clean and reuse 1 pipet) 2 10-ml volumetric pipets (or clean and reuse 1 pipet 1 suction device Notes Be sure to rinse each volumetric flask with distilled water prior to filing. Rinse each pipet 2 times with the solution to be transferred Rinse each cuvette once with the solution to be measured prior to filing. Caution: KMO's a strong oxidizer and is corrosive. Report spi ls to your instructor Part 1. Preparation of diluted solutions 1. Take a small amount of KMnO stock solution (-20 mL) to your bench. Using a pipet dispense 5.00 ml of the stock solution into a 50-mL volumetric flask. Dilute to mark with distilled water. Record concentration (M) in Data Table 1 . Fill cuvette # 1 with this solution. 2. Using a pipet dispense 5.00 ml of the solution you prepared in Step 1 into a 25-mL 3. Using a pipet dispense 10.00 mL of the solution you prepared in Step 2 into a 100- 4. Using a pipet dispense 20.00 mL of the solution you prepared in Step 3 into a 100- 5. Using a pipet dispense 10.00 ml of the solution you prepared in Step 4 into a 25-ml volumetric flask. Dilute with distilled water. Record concentration (Ma) in Data Table I. Fill cuvette #2 with this solution. ml volumetric flask. Dilute with distilled water. Record concentration (Ma) in Data Table 1, F l cuvette #3 with this solution. ml volumetric flask. Dilute with distilled water. Record concentration (Ma) in Data Table 1, Fill cuvette #4 with this solution. volumetric flask. Dilute with distilled water. Record concentration (Ms) in Data Table I. Fill cuvette #5 with this solution. Fill cuvette #6 with distilled water. Use it as a "blank" to zero the spectrophotometer. (The "blank contains disoving substance only absorbing species is 6. absent.) Data Table 1 Concentration and Color of Solutions Mi-Ms. Cuvette # | Concentration, M Color/No Color 2.0002 :00 00 2 Revised 08/2013 HRM

Explanation / Answer

there is no errors in the results you got and it seems to be you did follow the procedure correctly. usually maximum absorption of KMnO4 , inbetween 500-550nm. so the best absorption is at around 520nm. as you asked to make series of diluted KMnO4 latter concentrations ar too low and u would not get the straight line. because beer lambert law is work only at absoption range 0.2 to 0.7 . around that range only you get straight line as beer lambert law because beer lambert law follows only at that range. according to your procedure true that you get a curve for the final graph. and that is why in the question paper asked why is the graph is non linear.

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