Determination of Efficiency of Extraction
1. Prepare 250 ml of 0.05 M solution of NaOH from a 1M solution of NaOH. Keep the solution in a flask and label it properly.
2. From your instructor ask 35 ml of 1% aqueous solution of an organic acid and place it in a dry beaker
3. Using a clean pipette, measure exactly 10 ml of the acid solution into an Erlenmeyer flask and titrate this with the 0.05M NaOH using a drop of phenolphthalein indicator. Record to the nearest 0.1 ml, the volume of NaOH used in the titration. From this volume calculate the initial concentration of the acid solution.
4. Pipette another 10 ml of the acid solution into a separatory funnel or tube and extract it with 10 ml of solvent. If Ether is used, drain the lower aqueous layer into a flask. Pour the upper layer from the top of the funnel into a bottle labeled "ETHER EXTRACT" provided by your instructor.
5. Titrate the aqueous layer with 0.05M NaOH. Again, record to the nearest 0.1 ml, the volume of NaOH used. From this volume, calculate the amount of acid left in the aqueous layer. How much was extracted by 10 ml of the solvent?
6. Pipette another 10 ml of the acid solution into a separatory funnel. Extract the solution to twice with the solvent, each time using 5 ml of the solvent, Separate the aqueous layer, and titrate it with the 0.05M NaOH. Record the volume of the acid left after the two extractions. How much of the acid was extracted after the two extractions using a total of 10 ml solvent?