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酸碱滴定终点误差计算法

酸碱滴定终点误差计算法. 徐海超. 终点误差定义为 ：. 在化学计量点时满足 ：. ∑[ 得质子产物 ] sp = ∑[ 失质子产物 ] sp. 终点时 ：. 强酸强碱的滴定. 以 HCl 滴定 NaOH 为例. 化学计量点时：. [H + ] sp = [OH - ] sp. 终点时：. C x = [H + ] ep - [OH - ] ep. 强酸滴定弱碱 B -. [H + ] sp = [OH - ] sp +[B - ] sp. 化学计量点时：.

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酸碱滴定终点误差计算法

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  1. 酸碱滴定终点误差计算法 徐海超

  2. 终点误差定义为：

  3. 在化学计量点时满足： ∑[得质子产物] sp= ∑[失质子产物]sp • 终点时：

  4. 强酸强碱的滴定 • 以HCl滴定NaOH为例 • 化学计量点时： [H+]sp = [OH-]sp • 终点时： Cx = [H+]ep - [OH-]ep

  5. 强酸滴定弱碱B- [H+]sp = [OH-]sp +[B-]sp • 化学计量点时： Cx = [H+]ep - [OH-]ep - [B-]ep • 忽略[OH-]ep Cx = [H+]ep - [B-]ep

  6. 多元酸碱 Cx = [HPO42-]sp1 -[H+]sp1 - [H3PO4]sp • 以NaOH滴定H3PO4为例 • 化学计量点时： [H+]sp1 +[H3PO4]sp1 = [OH-]sp1 +[HPO4-]sp1 + 2[PO43-]sp1 • 忽略[OH-]， [PO43-]

  7. 混合酸碱 [H+]sp = [NH3] sp+ [OH-]sp • NaOH滴定HCl, NH4Cl混合溶液中的HCl 化学计量点时： Cx = [NH3]ep - [H+]ep

  8. 结论 • 写出化学计量点是的质子条件 • 做适当的忽略 • 将质子条件等式一边减去另一边得到 Cx，代入误差计算公式 • 根据相关条件几算出各形体浓度，从 而计算出滴定误差

  9. 附：证明 浓度为Ca的强酸滴定浓度CB弱碱B- • [H+]ep + [HB] ep – Caep = [OH-] ep • Caep – [HB] ep = [H+] ep – [OH-] ep • Caep – (CBep – [B-] ep) = [H+] ep – [OH-] ep • Caep – CBep = [H+] ep – [OH-] ep – [B-] ep 忽略[OH-] ep • CX = Caep – CBep = [H+] ep – [B-] ep

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