摘要
用氢氧化钠标准溶液滴定不锈钢电抛光溶液到第二化学计量点后,无法再进一步滴定HPO42-,测定出的磷酸含量要比真实值低。通过在第二化学计量点后加入适量钙盐的方法,判定Ca2+仅与HPO42-完全反应生成沉淀,而不会与其它阴离子反应,继续滴定释放出来的H+,便可测定出比较准确的磷酸含量。
In titrating the stainless steel electropolishing solution with sodium hydroxy standard solution, as HPO4^2- could not be titrated further after the second stoichiometric point, the phosphoric acid determining value was tower than the true value. An improved method can make the determining result more accurate. After reaching the second stoichiometric point, a feasible calcium salt is added into the titrating sample solution in a proper amount that is only sufficient to react with HPO4^2- entirely to form precipitati- on and release H^ ＋ while still not reacting with other anions in the sample. And then the released H ^＋ is titrated with the sodium hydroxy standard solution. Thus a more accurate determining result for phosphoric acid can be obtained.
出处
《电镀与精饰》
CAS
北大核心
2010年第4期33-35,共3页
Plating & Finishing
关键词
电抛光溶液
磷酸
第二化学计量点
钙盐
滴定
electropolshing solution
phosphoric acid
the second stoichiometric point
calcium salt
titratrate
作者简介
作者简介：魏新（1971-），男，辽宁沈阳人，新东北电气集团高压开关有限公司电镀分厂工程师．
