A sample of material contains for its active components NaOH, NażCO3, NaHCO3, or compatible mixtures of these. Two samples, each weighing 1.000 g, are dissolved in H20. To one sample phenolphthalein is added and the solution is titrated cold with 1.038 N acid, of which 17.96 mL is required. The other sample is titrated cold, with methyl orange as indicator, and 21.17 mL of the same acid is required. What alkalis are present, and what is the percentage of each in the original sample?

A sample of material contains for its active components NaOH, NażCO3, NaHCO3, or compatible mixtures of these. Two samples, each weighing 1.000 g, are dissolved in H20. To one sample phenolphthalein is added and the solution is titrated cold with 1.038 N acid, of which 17.96 mL is required. The other sample is titrated cold, with methyl orange as indicator, and 21.17 mL of the same acid is required. What alkalis are present, and what is the percentage of each in the original sample?

Principles of Modern Chemistry

8th Edition

ISBN:9781305079113

Author:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Publisher:David W. Oxtoby, H. Pat Gillis, Laurie J. Butler

Chapter15: Acid–base Equilibria

Section: Chapter Questions

Problem 99AP

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A sample may contain NaOH, NazCO3 and NaHCO3, alone or in some combination, along with inert material. A samplewitha mass of 857.6 mgwas dissolved and titrated with0.1163 M HCI. The volume of HCl used from 0 to methyl red endpoint (Phenolphthalein endpoint was not monitored here) was found to be 36.54 mL. Another 228.8 mg portion of the sample was titrated to the phenolphthalein endpoint and 10.82 mL was used up for this titration. a. What is the composition of the sample? b. Calculate the percentage of each of the component present.
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