K. I. Kump, F. A. Palocsay, and T. N. Gallaher'
Determination of the Percent Na4EDTA in Bathroom Cleaners
James Madison University Harrisonburg, Virginia 22801
T h e r e has been much publicity recently about t h e importance a n d virtues of relevant exoeriments i n chemistrv lahoratory courses, even to t h e extent of offering entire c&es o n t h e chemistrv of consumer eoods ( I ). T h e benefits of renewed interest i n and enthusiasm for laboratory experiments make t h e effort t o achieve relevance a rewardine exoerience aufor both t h e student and t h e instructor. I n this>o&al thors have treated t h e analysis of detergents for ohosohates . . in an effort t o make their lab courses d e d with environmental problems (2,3).McCormick (4) has pointed out the frequency with which EDTA titrations a r e encountered in t h e undergraduate laboratory, a n d t h a t student interest can he kept high by titrating atypical samples. 'Ihe following erperiment, designed for general chemistry students, involves the analysis of bathroom cleaners to determine theconrentratim uf t e t r a d i m ethylenediamineterraawULte( N d D T A I . The experiment clarifies for students the chemical basis for a praduet's composition and acquaints the student with complexometrie titrations. There are several different brands of bathroom cleaners on the market todav that claim to remove bathtub "rines" and hard water deposits. Todo this, the cleaner must Ire able t
