A quantitative analysis for ethanol, C2H6O, can be accomplished by a redox back titration. Ethanol is oxidized to acetic acid, C2H4O2, using excess dichromate, Cr2O7 2– , which is reduced to Cr3+. The excess dichromate is titrated with Fe2+, giving Cr3+ and Fe3+ as products. In a typical analysis, a 5.00-mL sample of a brandy is diluted to 500 mL in a volumetric flask. A 10.00-mL sample is taken and the ethanol is removed by distillation and collected in 50.00 mL of an acidified solution of 0.0200 M K2Cr2O7. A back titration of the unreacted Cr2O7 2– requires 21.48 mL of 0.1014 M Fe2+. Calculate the %w/v ethanol in the brandy

A quantitative analysis for ethanol, C2H6O, can be accomplished by a redox back titration. Ethanol is oxidized to acetic acid, C2H4O2, using excess dichromate, Cr2O7 2– , which is reduced to Cr3+. The excess dichromate is titrated with Fe2+, giving Cr3+ and Fe3+ as products. In a typical analysis, a 5.00-mL sample of a brandy is diluted to 500 mL in a volumetric flask. A 10.00-mL sample is taken and the ethanol is removed by distillation and collected in 50.00 mL of an acidified solution of 0.0200 M K2Cr2O7. A back titration of the unreacted Cr2O7 2– requires 21.48 mL of 0.1014 M Fe2+. Calculate the %w/v ethanol in the brandy

Chemistry: The Molecular Science

5th Edition

ISBN:9781285199047

Author:John W. Moore, Conrad L. Stanitski

Publisher:John W. Moore, Conrad L. Stanitski

Chapter10: Fuels, Organic Chemicals, And Polymers

Section: Chapter Questions

Problem 115QRT

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