难溶氢氧化物在纯水中的溶解度*

来源期刊：中南大学学报(自然科学版)1980年第3期

论文作者：张祥麟

文章页码：110 - 116

关键词：电离； 摩尔溶解度； 难溶氢氧化物； 多核； 文献； 溶度积； 纯水； 络离子； 金属氢氧化物； 氢氧根离子

摘    要：本文举例说明了从难溶的金属氢氧化物的溶度积计算其在纯水中的摩尔溶解度时,一方面必须考虑生成的多核和/或单核羟合络离子对溶解度的影响;另一方面,要注意纯水本身电离出来的那部分氢氧根离子的浓度,有时非但不能忽略,而且是主要的。有的教科书中由于忽视了这些问题而发生错误。进行教学时应注意正确处理这样的问题。

Abstract:

In calculating the solubility of sparingly soluble metal hydroxides in pure water,the effect of the formation of the hydroxy complexes,polynuclear and/or mononuclear,has to be considered.In addition,if S,the approximate value of the molar solubility of a metal hydroxide M（OH）n,is exceedingly low,nS<10^-7M,the hydroxide ions contributed by the dissociation of water itself must be taken into account in evaluating the pH value of the saturated aqueous solution.As a typical example,the solubility of ferric hydroxide in pure water was calculated with the consideration of the effect of the complexes [Fe（OH）]²⁺,[Fe（OH）₂]⁺,[Fe（OH）₃],[Fe（OH）₄]^- and[Fe₂（OH）₂]⁴⁺ formed in the aqueous solution,the pH value of the saturated solution being taken as 7.0,i.e.,the hydroxide ions liberated in the solution from the metal hydroxide itself being neglected.It may be worth mentioning that in Calculating the solubility of ferric hydroxide in pure water mistakes have been made by several authors,[1],