How do you determine the pKa of an acid?

1 Answer
May 13, 2016

Answer:

We would use the relationship, #pH=pK_a+log_10{[[A^-]]/[[HA]}}#

Explanation:

So the acid #HA# would be titrated with small aliquots of base while the #pH# of the solution was monitored with a #pH# meter. At the point of half equivalence (which would only be apparent after the endpoint!), #[A^-]=[HA]#, and #pH=pK_a# (because #log_(10)1=0#.