摘要
根据S2-与金属离子的沉淀反应以及H2S在水溶液中的的电离平衡,推导出了在pH<5时,以玻璃pH电极为参比,用硫电极测得硫离子滴定金属离子至化学计量点处的电动势值与pH值呈线性关系,而与其他因素无关;当控制溶液的pH值不变时,化学计量点处的电动势为一固定值.以此固定电位法对Pb2+,Cu2+试液进行了测定,最大相对平均偏差为1.1%,5次测定平均结果的相对百分误差最大为5.3%.
From the precipitation reaction based on S2-with metal ion and ionization equilibrium of H2S in aqueous solution,it could be deduced that the potential value at stoichiometric point was proportional to the pH value of solution and was independent of other factors when metal ion was titrated by S2-ion,by using pH glass electrode as reference electrode and sulfur electrode as measuring electrode at pH5.In addition,it could be found that the potential at stoichiometric point was invariable once pH value of solution is fixed.Sample solutions including Pb2＋ and Cu2＋ were measured through this fixed potential method.The results indicated that the maximum relative deviation was 1.1% and the maximum relative error of five measurement values was 5.3%.
出处
《中北大学学报（自然科学版）》
CAS
北大核心
2011年第4期477-481,共5页
Journal of North University of China(Natural Science Edition)
