Question

A 50.0mL aliquots of a 0.3000M solution of Compound A is extracted with 50.0mL of Diethyl Ether. Titration of the extracted aqueous solution required 23.50mL of 0.5000M NaOH. Calculate the Distribution Coefficient (K_D) of Compound A.

Please show all work with relevant formulas. Thank you!

Answer 1

Distribution coefficient

KD = solubility of solute in organic phase / solubilty of solute in aqueous phase

solubility of solute in organic phase = Meq of acid in ether/volume of ether

= (Meq of acid in initial aqueous phase - Meq of acid in extracted aqueous phase) /volume of ether

= (50 mL x 0.3 M - 23.5 mL x 0.5 M) /50 mL

= (15 - 11.75) /50 mL

= 3.25 Meq / 50 mL

solubilty of solute in aqueous phase = Meq of acid in extracted aqueous phase / volume of water

= 11.75 Meq / 50 mL

KD =( 3.25 Meq / 50 mL) / (11.75 Meq / 50 mL)

KD = 0.277