A 0.400-g sample of toothpaste was boiled with a 50-mL solution containing a citrate buffer and NaCl to extract the fluoride ion. After cooling, the solution was diluted to exactly 100 mL. The potential of an ion-selective electrode with a Ag-AgCl(sat'd) reference electrode in a 25.0-mL aliquot of the sample was found to be -0.1823 V. Addition of 5.0 mL of a solution containing 0.00107 mg F™/mL caused the potential to change to -0.2446 V. Calculate the mass percent- age of F in the sample.

A 0.400-g sample of toothpaste was boiled with a 50-mL solution containing a citrate buffer and NaCl to extract the fluoride ion. After cooling, the solution was diluted to exactly 100 mL. The potential of an ion-selective electrode with a Ag-AgCl(sat'd) reference electrode in a 25.0-mL aliquot of the sample was found to be -0.1823 V. Addition of 5.0 mL of a solution containing 0.00107 mg F™/mL caused the potential to change to -0.2446 V. Calculate the mass percent- age of F in the 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

Chapter23: Potentiometry

Section: Chapter Questions

Problem 23.24QAP

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