High School Chemistry Students’ Alternative Conceptions of H2O, OH-, and H+ in Balancing Redox Reactions

Abstract

There are a number of research works into alternative conceptions for the purposes of identifying, categorising, and designing instructional approaches to help address them. The current study sought to find out high school students’ alternative conceptions in the introduction of H2O, H+, and OH- in oxidation-reduction reactions in acidic and basic media when balancing the chemical equations using the ion-electron method. Two of the 20 two-tier diagnostic test items were used to survey the conceptions of 213 students in balancing oxidation-reduction reactions. The 213 students were randomly selected from three of the seven elective science schools in three districts assemblies of the Ashanti Region of Ghana. The findings from the descriptive quantitative data analysis show that the students have conceptual difficulties in the concept. Qualitatively, the identified students’ alternative conceptions included introduction of H2O molecules in acidic medium is to dilute the system; H+ ions in a basic medium is to neutralise the OH- ions of the base; and OH- ions is to make the system basic. It is therefore recommended that the chemical instructional designers should design a pedagogical content knowledge for the teaching and learning of balancing oxidation-reduction reactions.