Quantitative Evaluation of Dissociation Mechanisms in Methylorange and Methylred

Abstract

Several computational chemistry programs were evaluated as aids to teaching a part of qualitative analytical chemistry. Computational chemical calculations can predict absorption spectra, thus enabling the modeling of indicator dissociation mechanisms using a personal computer. An updated MNDO program among 51 programs was previously found to be the best predictor to explain the dissociation mechanisms of isobenzofuranones and sulfonephthaleins. Therefore, the further quantitative analysis was performed for methyl-orange and methyl-red. Computational chemical analysis can be used for quantitative explanation of indicator dissociation mechanisms.