磷酸电位滴定.docx

磷酸的电位滴定药学院10级4小班 王凌阳 10011020096【实验目的】1 掌握电位滴定的方法及确定化学计量点的方法2 用电位滴定法测定磷酸的量浓度【方法提要】1 电位滴定法主要 针对一般容量滴定不能进行的测定，如被测液浑浊或本身有颜色等。电位滴定法还可以用于寻找合适指示剂或校正指示剂的终点颜色变化2 电位滴定法可用来测定某些电力平衡常数【试剂和仪器】酸度计、复合电极、电磁搅拌器、搅拌子、移液管（10ml）、烧杯（100ml）NaOH标准溶液（1mol/L），磷酸样品溶液（1mol/L）【操作步骤】精密吸取磷酸样品溶液10.00毫升，置于烧杯中，加蒸馏水50毫升，插入复合电极，以NaOH 标准液滴定，记录滴定剂体积及对应pH值，计算H3PO4的浓度。【数据记录与处理】磷酸电位滴定数据记录体积电位（mv）一次导数二次导数0291.25263.5-5.545.71254.1-13.13-10.6596.36246.2-12.969-4.0136.71240.8-15.471-7.1047234.7-20.443-16.8027.41224.7-23.51215.0417.62215.9-40.422-78.5697.73209.8-56.727-149.1817.82204.3-62.304-63.1757.98191.1-82.128-50.1268.06179.8-146.094-826.9998.22137.4-346.637-2065.7998.25130.8-272.7513030.4388.3121.9-24.1610431.138.37106.8-25.7716276.6178.6382.3-19.1161899.7878.781.3-15.85951.659.0564.8-12.036616.2249.2459-3.341630.6399.5154.5-12.09664.7949.8744.4-13.862179.19510.0439.9-26.4-72.74610.238.6-8.169119.14310.9626.9-18.482-20.1111.4420.6-16.078-26.2171212.6-17.455-22.31712.794.2-10.77811.29213.15-0.3-11.949-3.17913.54-5.7-14.279-6.10414.21-14.6-18.234-29.79715.03-29-25.851-49.59715.51-40.1-30.3871.32416.01-59.3-45.574-62.33316.36-87.3-119.706-454.01816.45-102.3-182.471-386.80316.49-112.2-251.807-1754.70116.52-121.1-318.986-2421.37916.54-125.6-178.4165573.31716.6-139.8-252.756227.55916.63-146.3-198.241662.651【曲线图】E-V 曲线图一阶微商二阶微商【结论】终点一 体积8.316ml 电位116.0mV 浓度0.0832mol/L终