Thursday 15 October 2015

Titration Curves

During a titration, the pH does not change uniformly. There are key points that can be calculated, and the remainder of the curve can be sketched from these:

Initial pH

This example starts with a weak acid in the conical flask. If it were a weak base, the calculations are a lot harder, but you can refer to THIS for how to do that calculation.



Equivalence Volume and Half-Equivalence Point

This relies on a good memory of the titration topic from last year. Once you know the equivalence volume, you are ready to mark the pH of the half-equivalence volume (pKa = pH).



Final pH

This is very easy if you remember how to calculate the pH of a strong base (in this example). Put all of these points together to sketch the shape of the curve.



Equivalence Point pH

This is very hard and seldom asked in NCEA. Having said that, maybe this is the year that it will be asked...

We will cover this in Friday's lesson and dedicate an entire blog post to it.



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