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Acid–Base Titration
Ammonia Titration Curve with HCl
Description
Ammonia titration with hydrochloric acid shows how a weak base behaves as acid is added. The curve is the mirror image of a weak acid titrated with a strong base. In this case, ammonia acts as the weak base, and hydrochloric acid acts as the strong acid.
The starting pH of 50 mL of 0.1 M ammonia ...
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Transcript
弱碱与强酸滴定曲线是弱酸-强碱滴定曲线的逆向过程。
氨水会形成铵根离子和氢氧根离子。根据ICE表格和Kb表达式的计算，50 mL 0.1 M氨溶液的初始pH值为11.11，呈碱性。
向氨溶液中加入 25 mL 0.1 M 盐酸后，所得缓冲液中含有等量的氨和铵离子。通过将这些值代入 Henderson-Hasselbalch 方程，可计算该缓冲液的 pH。此时，pH 等于 pKa。
在滴定终点时，加入的 50 mL 盐酸将所有氨完全转化为铵离子。这些铵离子发生水解，生成水合氢离子，使溶液呈酸性，pH 为 5.28。
在等当点之后，随着水合氢离子占主导，...
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