【摘要】 在NH₄Ac底夜中,MO（Ⅵ）可直接用标准Pb²+滴定,利用Pb²+切口产生指示终点,若是Cd-Mo混合溶液,还能连续测定。先用EGTA滴定Cd²+,然后用Pb²+直接滴定Mo。W-Mo合金中Mo的测定也只需将W（Ⅵ）沉淀为钨酸,用干过滤法分离部分滤液,直接测Mo,可得满意结果。在同样底液条件下。W（Ⅵ）则需要加过量标准Pb²+生成PbWO₄沉淀,过量Pb²+再用标准EDTA反滴定,以Pb²+切口消失指示终点。用此法作了纯钨粉及钨铁合金标样测定。更多还原

【Abstract】 In NH₄Ac solution Mo（Ⅵ）can be di-tectly titrated by standard Pb （Ⅱ）solu- tion using the appearance of Pb incision to indicate the end-point. Cd²⁺present in the solution can be titrated by EGTA followed by successive titration of MOO₄^2- by Pb²⁺. In the analysis of 1:1 W-Mo alloy, W（Ⅵ）is separated from Mo（Ⅵ）by precipitation as tungstic acid, part of the solution containing the precipitate is filtered through dry filter, paper, and the MoO₄^2-content in the filtrate is deter-mined by direct titration with Pb²⁺solu-tion. In NH₄Ac Solution WO₄^2-can be determined by precipitation with excess standard Pb²⁺solution, followed by ti-tration of excess Pb²⁺with EDTA.更多还原