摘要：采用光谱分析方法研究了连二硫酸水溶液的稳定性与酸度、温度、时间的关系：当酸度为1.0mol/L的时候，连二硫酸水溶液较稳定，酸度增至7.0mol/L开始分解明显；在沸水浴条件下，酸度为1.0mol/L的时候连二硫酸即开始分解；高氯酸浓度为6mol/L的连二硫酸溶液在一个小时内没有明显的分解。研究了重量法测定连二硫酸盐含量的条件：加入等体积的过氧化氢，加入高氯酸至浓度为7mol/L，沸水浴加热半个小时，连二硫酸完全氧化为硫酸根，加入BaCl2溶液，生成硫酸钡沉淀，按重量分析法测定。比较了重量法与重铬酸钾法测定连二硫酸的结果，二方法测定结果相近，重量法可行。

关键词：连二硫酸锰；过氧化氢；紫外光谱；重量法

Abstract:The relationship of stability of dithionic acid with acidity, temperature and time was studied by spectral analysis. dithionic acid was stable in the 1.0 mol/L perchloric acid, and it became to decompose significantly when concentration of perchloric acid increased to 7.0 mol/L. In boiling water bath dithionic acid began to decompose at 1.0mol/L perchloric acid and at room temperature its decomposition didn’t observed until concentration of perchloric acid to 6 mol/L after one hour. The conditions of determing content of dithionic acid by gravimetric analysis was researched. The methode are the following: addition of isopyknic 30% H2O2 to dithionic acid solution and of perchloric acid to 7 mol/L, heating for 0.5h in boiling water, oxidation of dithionic acid to sulfate completely, addition of BaCl2 solution over stoichiometric value, content of dithionic acid is measured by Gravimetric method. Compare of concentration of dithionic acid determined by two methods showed the results was closely. The gravimetric method demonstrates feasibility of the method proposed.

Key words: Manganese dithionate; Hydrogen peroxide; Ultraviolet spectrum; Gravimetric method