Visual demonstration of the ionic strength effect in the classroom: the Debye-Hückel limiting law

Química Nova

Edvaldo Sabadini¹  Larissa Vieira Cavalcanti Carvalho¹ 

[1] ,Universidade Estadual de Campinas Instituto de Química Departamento de Físico-QuímicaCampinas SP ,Brasil

关键词: color change;    ionic strength effect;    visualization of the Debye-Hückel law;   

DOI  :  10.1590/S0100-40422013000100031

来源: SciELO

【 摘 要 】

The effects of ionic strength on ions in aqueous solutions are quite relevant, especially for biochemical systems, in which proteins and amino acids are involved. The teaching of this topic and more specifically, the Debye-Hückel limiting law, is central in chemistry undergraduate courses. In this work, we present a description of an experimental procedure based on the color change of aqueous solutions of bromocresol green (BCG), driven by addition of electrolyte. The contribution of charge product (z+|z-|) to the Debye-Hückel limiting law is demonstrated when the effects of NaCl and Na2SO4 on the color of BCG solutions are compared.

【 授权许可】

CC BY-NC   
 All the contents of this journal, except where otherwise noted, is licensed under a Creative Commons Attribution License