posted by jmf on .
I am having trouble coming up with a lab to determine the pka of salicyclic acid! help1
Weigh amount SA accurately. Titrate manually with a standard solution of NaOH and plot on a sheet of graph paper (pH on y axis and mL on x axis). (Use an indicator to tell when you have reached the equivalence point). Then read the pH at the half-way mark to the equivalence point. That will be the pKa of SA. Good luck.
There is another, probably easier way to do it IF you have the materials.
Weigh accurately SA. Convert to moles.
Weigh accurately the sodium salt of SA (you want to weigh an amount to provide an equal number of moles). Drop in water and measure the pH. That will be the pKa.