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一般作酸碱滴定时,多采用甲基橙等为指示剂。因其颜色关系,使终点不易辨认,特别是在阴天或灯光下进行工作时,最容易发生误差。本文介绍一种比较价廉而敏感性强的混合指示剂,其原理是根据某些有机物,能在一定 pH 范围内的变色,视其颜色变化程度的大小,以测定溶液内的 pH 值。这种混合指示剂颜色转变过程中,变化比较明显,阶段分清,因而在终点未到达以前,能示以预兆,增加了滴定时的准确性,可以缩短工作时间,提高工作效率。
Usually acid-base titration, the more use of methyl orange as an indicator. Because of its color relationship, so that the end is not easy to identify, especially in cloudy or light work, the most prone to error. This article describes a more affordable and sensitive mixed indicator, the principle is based on certain organic substances, can be within a certain pH range of color, depending on the extent of its color change to determine the pH value within the solution. This mixed indicator color change process, the change is more obvious, the stage clear, and therefore did not arrive before the end, can show signs, increasing the titration accuracy, can shorten the working hours and improve work efficiency.