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一、方法原理: 1。当指示电极与参比电极同时浸入试液中时,构成一个原电池,根据滴定过程中,测定原电池的电动势,在等当点附近时,由于被测物质浓度改变,曾引起电位的突跃,即可求得被测离子的浓度。 2、应用G—SZ—2型离子计,以甘汞电极作为参比电极,铂电极为指示电极,加入标准NaNO_2溶液,滴定时离子计所指示的数字,表示两个电极之间电位的变化,当加入0.05ml(0.10ml)的NaNO_2溶液时,离子计读数有最大的跳跃时,即为滴定终点。
First, the principle of the method: 1. When the indicator electrode and the reference electrode are immersed in the test solution at the same time, a galvanic cell is formed. According to the titration process, the electromotive force of the galvanic cell is measured. When the concentration of the test substance is changed, a sudden jump in potential occurs , You can get the measured ion concentration. 2, the use of G-SZ-2-type ion meter with calomel electrode as the reference electrode, platinum electrode as the indicator electrode, adding standard solution of NaNO_2, titration when the meter indicated by digital, that the potential change between the two electrodes , When adding 0.05ml (0.10ml) of NaNO_2 solution, the ion meter reading has the largest jump, is the end of the titration.