Common student misconceptions in electrochemistry: Galvanic,electrolytic, and concentration cells

This study replicates, with additions, research done by Garnett and Treagust. Garnett and Treagust's interview questions for galvanic and electrolytic cells were used with modifications; concentration cell questions were asked in a similar manner. These questions were administered to 16 introductory college chemistry students after electrochemistry instruction. Student misconceptions most commonly encountered included notions that electrons flow through the salt bridge and electrolyte solutions to complete the circuit, plus and minus signs assigned to the electrodes represent net electronic charges, and water is unreactive in the electrolysis of aqueous solutions. New misconceptions identified included notions that half-cell potentials are absolute and can be used to predict the spontaneity of individual half-cells, and electrochemical cell potentials are independent of ion concentrations. Most students demonstrating misconceptions were still able to calculate cell potentials correctly, which is consistent with research suggesting that students capable of solving quantitative examination problems often lack an understanding of the underlying concepts. Probable origins of these student misconceptions were attributed to students being unaware of the relative nature of electrochemical potentials and chemistry textbooks making misleading and incorrect statements. A minor technical flaw in the Garnett and Treagust study is also addressed. J Res Sci Teach 34: 377–398, 1997.