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

Quimica nova

Carvalho, Larissa Vieira Cavalcanti¹  Sabadini, Edvaldo¹ 

[1] Universidade Estadual de Campinas, Campinas, Brasil

关键词: color change;    ionic strength effect;    visualization of the Debye-Hü;    ckel law.;   

DOI  :  10.1590/S0100-40422013000100031

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 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