Practice question · Multiple choice
Why does the equivalence point of a weak acid titrated with a strong base lie above pH 7?
Hints
- At equivalence, exactly what species is left in the flask?
- The salt of a weak acid contains a conjugate base that takes protons from water.
Show the answer
B. The conjugate base of the weak acid remains in solution and hydrolyses
Why
At equivalence the acid is entirely converted to its conjugate base, which is a genuine weak base and hydrolyses water to give hydroxide. There is no excess titrant at that point, the basicity comes from the salt itself.
Practise Buffers, Hydrolysis and Titration
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