# Pka and solubility

by accarter15
Tags: solubility
 P: 1 The pKa of p-nitrophenol is 7.15. Would you expect it to dissolve in sodium bicarbonate solution? The pKa of 2,5-dinitrophenol is 5.15. Will it dissolve in bicarbonate solution. Pka of bicarbonate solution is 6.34. Any help will be greatly appreciated, thanks.
P: 22,361
 Quote by accarter15 Pka of bicarbonate solution is 6.34.
That was pH I suppose?

Both substances will dissolve if converted to ions. Use Henderson-Hasselbalch equation to calculate how much of the substance will be in the ionic form.

 Sci Advisor HW Helper P: 1,769 at equal concentrations of p-nitrophenol and its conjugate base, the solution will be basic, since pKa=pH at equal concentrations. This means that the molecule has basic characteristics (the alcohol motif), assuming that p-nitrophenol is insoluble in pure water, than in an acidic solution of bicarbonate.......think about the common ion effect. You should apply the same reasoning with your other compound.