P856b: Turbidimetry in the undergraduate analytical or instrumental analysis laboratory: An analysis of chloride ion in sports drinks

Author: Dinty J. Musk Jr., Ohio Dominican University, USA

Co-Author: Dean Dziewit and Lewis Hogarth, Ohio Dominican University, USA

Date: 8/6/14

Time: 2:15 PM2:25 PM

Room: MAK B1120

Related Symposium: S57

While turbidimetry is a versatile technique for quantification of many analytes, its incorporation in the undergraduate analytical or instrumental analysis laboratory seems to be sparse. Compared to gravimetry, titration, and other techniques turbidimetry is singularly sensitive to thoughtful and careful sample preparation. Thus, an experiment in turbidimetric analysis is an ideal inclusion into the instrumental analysis laboratory sequence to reinforce the need for fastidious sample preparation. We have developed a robust, relevant, and relatable example of such an analysis for use in the analytical chemistry laboratory: the quantification of chloride in sports drinks by analysis of AgCl turbidity.

P856a: When indicators lie: Acid-Base titration of a household drain cleaner

Author: Dinty J. Musk Jr., Ohio Dominican University, USA

Co-Author:

Date: 8/6/14

Time: 2:05 PM2:15 PM

Room: MAK B1120

Related Symposium: S57

Acid-base titrations of household goods like vinegar, antacids, lemon juice, milk, etc. are staple experiments in the General Chemistry laboratory curriculum. Quantitative determination of acid or base in these analytes is most often accomplished with an indicator such as phenolphthalein as a visual measure of reaction completion. For an exercise in problem solving and discovery-based learning, a household drain cleaner was given to students for titrimetric analysis that contained a solution of hydroxide ion and also hypochlorite ion. The hypochlorite will readily render most indicator dyes colorless, preventing colorimetric determination of the equivalence point of this acid-base titration. Students were forced to go “off-script” to improvise an alternate procedure for finding the concentration of hydroxide in the solution using pH meters. This improvisation led to enhanced understanding of the role of the indicator in acid-base titrations and better comprehension of titration curves in general.

P705: When indicators lie: Acid-base titration of a household drain cleaner

Author: Dinty J. Musk Jr., Ohio Dominican University, USA

Co-Author: William Urban, North Central State College, USA

Date: 8/6/14

Time: 11:30 AM11:50 AM

Room: LOH 164

Related Symposium: S41

Acid-base titrations of household goods like vinegar, antacids, lemon juice, milk, etc. are staple experiments in the General Chemistry laboratory curriculum. Quantitative determination of acid or base in these analytes is most often accomplished with an indicator such as phenolphthalein as a visual measure of reaction completion. For an exercise in problem solving and discovery-based learning, a household drain cleaner was given to students for titrimetric analysis that contained a solution of hydroxide ion and also hypochlorite ion. The hypochlorite will readily render most indicator dyes colorless, preventing colorimetric determination of the equivalence point of this acid-base titration. Students were forced to go “off-script” to improvise an alternate procedure for finding the concentration of hydroxide in the solution using pH meters. This improvisation led to enhanced understanding of the role of the indicator in acid-base titrations and better comprehension of titration curves in general.