Use of EDTA disodium salt as standard for preparation of solutions

Química Nova

Oliveira, Andrea¹  Medeiros, Lívia Soman de¹  Neves, Eduardo F. de Almeida¹  Universidade Federal de São Carlos, São Carlos, Brasil¹  Silva, Paulo H. Pereira da¹ 

关键词: EDTA;    standard;    potentiometry.;   

DOI  :  10.1590/S0100-40422007000300013

学科分类：化学（综合）

来源: Sociedade Brasileira de Quimica

【 摘 要 】

The hydrated sodium salt of EDTA, Na2H2Y·2H2O, cannot be used as a primary standard for titrations due to uncertainties in the water content. An alkalimetric titration of the homogenized solid in the presence of a small excess of BaCl2·2H2O allows one to titrate quantitatively the released two hydrogen cations with end-point indication by phenolphthalein or potentiometry. This leads one to calculate the average molar mass of the reagent and its water content, allowing to use it to prepare EDTA standard solutions. One titrated sample led to the formula Na2H2Y·1.876 H2O, and 370.01 g.mol-1 for the average molar mass.

【 授权许可】

Unknown