Coulometric titration with higher oxidation states of manganese: Electrolytic generation and stability of +3 manganese in sulfuric acid media
Coulometric titration with higher oxidation states of manganese: Electrolytic generation and stability of +3 manganese in sulfuric acid media
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DOI：
10.1016/0003-2670(59)80233-6
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发表时间：
1959
影响因子：
6.2
通讯作者：
R. Selim;J. Lingane
中科院分区：
文献类型：
--
作者：
R. Selim;J. Lingane
用电化学方法计算了在硫酸介质中+3价锰还原成+2和+4价锰的平衡常数。在25 ℃时，在4 M硫酸中的表观电离常数为10 ~（-3），在7 M硫酸中为10 ~（-4）。在5 ~ 7 M的硫酸中，+3和+4锰对水的还原和氧化物的沉淀都很稳定。在2 ~ 7 M硫酸溶液中，当+2价锰的浓度至少为0.2M时，产生+3价锰的电流效率接近100%。当产生+3锰用于库仑滴定时，约6 M的硫酸浓度是最令人满意的，因为+3锰在该介质中最稳定。
The equilibrium constant for the disproportionation of +3 manganese into the +2 and +4 states in sulfuric acid media has been evaluated spectrophotometrically. The formal disproportionation constant varies from 10-3in 4Msulfuric acid to 10-4in 7Msulfuric acid at 25°. In 5 to 7Msulfuric acid both +3 and +4 manganese are quite stable with respcct to both their reduction by water and to the precipitation of their oxides. The current efficiency for the generation of +3 manganese is nearly 100% in 2 to 7Msulfuric acid solution, providing the concentration of +2 manganese is at least 0.2M. A sulfuric acid concentration of about 6Mis most satisfactory when +3 manganese is generated for coulomctric titration because of the maximal stability of +3 manganese in this medium.