“…Results of this study are in line with the results of some previous studies [18,19]. According to the study of Dindar et al (2010) [18], as regard acids and bases concepts, results revealed that all CPSTs explained incorrectly the acid and base definition regarding Bronsted-Lowry and Lewis acid-base definitions. Besides, all of them stated that they could not understand neither a matter is an acid nor a base using a litmus paper.…”