Question

Is a pK_a value determined more reliably via equivalence point or end point? Please explain. It's part of a lab report and our professor seems insistent one is more reliable than the other

Answer 1

Clearly to answer this question you must know the difference between equivalence point and end-point.
The equivalence point is the point where moles of titrant = moles of analyte whereas end point is
the point where we observe the color change of the indicator.
Always remember that, end point is always close enough or an approximation to equivalence point which
of course depends upon how you perform the titration. If done properly then the end-point will be significantly
very close to equivalent point.
Hence, pKa value determined via equivalence point is more reliable.