Emprego do sal di-sódico de edta como padrão no preparo de soluções

Química Nova

Paulo H. Pereira Da Silva¹  Andrea Oliveira¹  Lívia Soman De Medeiros¹  Eduardo F. De Almeida Neves¹ 

[1] ,Universidade Federal de São Carlos Departamento de Química São Carlos SP ,Brasil

关键词: EDTA;    standard;    potentiometry;   

DOI  :  10.1590/S0100-40422007000300013

来源: SciELO

【 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】

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