The partition coefficient, Kpc, shows the distribution of a solute between two immiscible solvents. Kpc is determined by measuring the concentration of the solute in each solvent. The organic solvent ethoxyethane, CH3CH2OCH2CH3, and water are immiscible. A student is asked to find Kpc of butanedioic acid, HOOCCH2CH2COOH, between ethoxyethane and water. The expression for Kpc when butanedioic acid is in equilibrium between ethoxyethane and water is shown. Kpc = [HOOCCH2CH2COOH(ethoxyethane)] [HOOCCH2CH2COOH(aq)] [density: ethoxyethane, 0.71gcm¯³; water, 1.00gcm-³] The student uses the following method to find the partition coefficient. A diagram of the apparatus is shown in [Figure 1.1]. step 1 Add 30.0cm³ of distilled water to a separating funnel. step 2 Weigh by difference 2.81 g of butanedioic acid into the separating funnel. step 3 Stopper the separating funnel and shake it until the butanedioic acid has dissolved. step 4 Remove the stopper and add 30.0cm³ of ethoxyethane to the separating funnel. step 5 Replace the stopper and shake the separating funnel gently. step 6 Place the separating funnel into a clamp. Allow the liquids to settle so that the two layers can be seen. step 7 Remove the stopper and open the separating funnel tap to allow the lower layer to run into a beaker labelled A. Run the upper layer into a beaker labelled B. step 8 Transfer 10.0cm³ of the aqueous layer into a conical flask. Titrate with 0.500moldm-3 NaOH(aq). Use thymolphthalein as the indicator. step 9 Take 10.0cm³ of the ethoxyethane layer and add 10.0cm³ of water to it. Titrate this mixture with 0.100 moldm¯³ NaOH(aq). Use thymolphthalein as the indicator.