Acids and Bases: The Appropriation of The Arrhenius Model by Tunisian Grade 10 Students

In this work, we propose to identify the knowledge that Tunisian grade 10 students build up concerning acids and bases. Thus, after learning, we have proceeded by giving a paper and pencil task to students of two levels of teaching. The results obtained allow us to say that the assimilated knowledge is transitory; that the students have a worse perception of the base than of the acid concept and these two concepts are independent; that they associate the acid or base strength to its concentration; that the pH is far from being a “tool” of estimation of the degree of acidity; and that the students have difficulty in linking the empirical and the models’ registers. Moreover, some alternative conceptions that can be harmful to the learning of Brønsted’s model appear.