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存在滴定突跃是滴定分析可以进行的先决条件。国内教科书讨论突跃范围的概念时均利用了滴定分数100±0.1%的条件,即按照滴定分数99.9%和100.1%来计算突跃范围。实际上,滴定过程中滴定剂是以液滴为单位加入到被测溶液中的,指示剂滴定法中也是以一滴或半滴标准溶液加入后被测溶液颜色发生改变来确定终点的,因此,按照化学计量点前后欠缺或过量半滴标准溶液来计算突跃范围更具科学性和实用价值。本文将计量点附近单滴滴定剂加入被测溶液引起的p H变化定义为突跃范围。对强碱滴定一元强酸体系的突跃范围进行了数学计算。结果表明,突跃范围与被测溶液的体积和浓度、滴定剂的浓度和液滴尺寸、被测溶液和滴定剂的浓度比等因素都有密切相关性,给出了不同于教科书的某些重要结论,这些新结论与实际滴定情形相符,对指导滴定分析具有重要参考价值。
The presence of titration jumps is a prerequisite for the titration analysis to proceed. Domestic textbooks to discuss the concept of sudden range are used titration score 100 ± 0.1% of the conditions, that is, according to the titration score of 99.9% and 100.1% to calculate the range of the jump. In fact, during the titration titrant is added to the measured solution as a droplet, the indicator titration method is also used to determine the end of the color change of the test solution after a drop or a half drops of standard solution is added, In accordance with the stoichiometric point before or after half a drop of standard solution to calculate the sudden jump range more scientific and practical value. In this paper, the change of p H caused by adding a single titrant near the measurement point to the solution under test is defined as the range of the jump. The leaping range of strong acid titration monobasic acid system was calculated. The results show that the range of the jump is closely related to the volume and concentration of the solution to be measured, the concentration of the titrant and the size of the droplet, and the concentration ratio of the solution to be measured and the concentration of the titrant. Some of the factors Important conclusions: These new conclusions are in line with the actual titration situation and have important reference value for guiding titration analysis.