If an organic acid of pKa 4 and K = 25 (in extraction with pentanol) is in aqueo
ID: 492534 • Letter: I
Question
If an organic acid of pKa 4 and K = 25 (in extraction with pentanol) is in aqueous solution with an organic base of pKa 9 and K = 35 (in extraction with pentanol), in what phase will they primarily be found if the aqueous phase is pH'ed to 7?
A. Both will be found primarily in the aqueous phase.
B. The acid will be primarily in the organic phase while the base will remain primarily in the aqueous phase.
C. The base will be primarily in the organic phase while the acid will remain primarily in the aqueous phase.
D. Not enough information is provided to determine the answer.
E. Both will be found primarily in the organic phase.
Explanation / Answer
As the pka of the acid is 4, it will be deprotonated at pH = 7 . Similarly as the pKa of the base is 9 , it will be protonated (as RNH3+) at pH = 7. So, both the compounds will exit intheir salt form and will be present in the aqueous phase.
Correct answer : A