Isoelectric point vs equivalence point

[Hemichordate]

So let me see if I have this right:

Isoelectric point: Zero net charge (exists as zwetterion)
Equivalence point: Have equal concentrations of acid and base

Would these two points always be the same when a strong acid is titrated with a strong base (or vice versa)?

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[Rabolisk]

No. If HA is fully titrated with a base OH- you would have A- left over which is negative.

 

[Hemichordate]

Ok, I see.

Also, does the average of two pKa's give you the isoelectric point value or the equivalence point value? I've seen sources that claim either one.

 

[Rabolisk]

Both in specific cases. Isoelectric point is when the molecule only applies when you have something like an amino acid that has multiple acidic protons and at some intermediate point can exist as a neutral molecule. All titrations involving diprotic acids have an equivalence point between two pKas, but only select molecules have an isoelectric point there as well.

 

[wahcha]

Both in specific cases. Isoelectric point is when the molecule only applies when you have something like an amino acid that has multiple acidic protons and at some intermediate point can exist as a neutral molecule. All titrations involving diprotic acids have an equivalence point between two pKas, but only select molecules have an isoelectric point there as well.

Rabolisk, you're a genius. Your answers are always spot on and I find 'em in half the posts I care to read. Thanks for the contributions buddy!