Use of EDTA disodium salt as standard for preparation of solutions

Quimica nova

Oliveira, Andrea¹  Medeiros, Lívia Soman de¹  Neves, Eduardo F. de Almeida¹  Silva, Paulo H. Pereira da¹ 

[1] Universidade Federal de São Carlos, São Carlos, Brasil

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 sodiumsalt of EDTA, Na2H2Y·2H2O, cannot beused as a primary standard for titrations due to uncertainties in the watercontent. An alkalimetric titration of the homogenized solid in the presenceof a small excess of BaCl2·2H2O allows oneto titrate quantitatively the released two hydrogen cations with end-point indicationby phenolphthalein or potentiometry. This leads one to calculate the averagemolar mass of the reagent and its water content, allowing to use it to prepareEDTA standard solutions. One titrated sample led to the formula Na2H2Y·1.876H2O, and 370.01 g.mol-1 for the average molar mass.

【 授权许可】

CC BY