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19 Nov 2019
Student Name: TA Name Experiment 3: Acid/Base Extraction the following questions. Limited partial credit will be given. 1. A student performs the following to biphenyl and salicylic acid. steps to isolate biphenyl from a solid 1:1 mixture of a. Dissolve 2.0 grams of the mixture in 20 mL of ether b. Extract the ether layer 2-3 times with an aqueous solution of 5% sodium c. Add 2-3 spatula tips of sodium sulfate to the ether layer d. Extract the ether layer with a saturated aqueous solution e. Isolate the organic layer and evaporate the ether. sold they collect at the end weighs 1.23 g and has a wide melting point range. based on the The If the student expected to recover 1 gram of pure biphenyl, explain procedural information given above, why this student did not see results. Hint: The order of steps in an extraction can be important. their expected The mixture of benzoic acid, biphenyl, and benzocaine used in this experiment is soluble in acetone, a low boiling point organic solvent. Why would this be a poor choice of organic solvent for this experiment? Hint: think about what the requirements are for the solvents in an effective liquid-liquid extraction 2. 3. Explain why saturated sodium chloride solution is used in liquid-liquid extractions. Can the mixture of benzoic acid, biphenyl, and benzocaine still be separated from one another if 5% hydrochloric acid is added at the beginning of the extraction instead of 5% sodium bicarbonate? Explain your answer 4.
Student Name: TA Name Experiment 3: Acid/Base Extraction the following questions. Limited partial credit will be given. 1. A student performs the following to biphenyl and salicylic acid. steps to isolate biphenyl from a solid 1:1 mixture of a. Dissolve 2.0 grams of the mixture in 20 mL of ether b. Extract the ether layer 2-3 times with an aqueous solution of 5% sodium c. Add 2-3 spatula tips of sodium sulfate to the ether layer d. Extract the ether layer with a saturated aqueous solution e. Isolate the organic layer and evaporate the ether. sold they collect at the end weighs 1.23 g and has a wide melting point range. based on the The If the student expected to recover 1 gram of pure biphenyl, explain procedural information given above, why this student did not see results. Hint: The order of steps in an extraction can be important. their expected The mixture of benzoic acid, biphenyl, and benzocaine used in this experiment is soluble in acetone, a low boiling point organic solvent. Why would this be a poor choice of organic solvent for this experiment? Hint: think about what the requirements are for the solvents in an effective liquid-liquid extraction 2. 3. Explain why saturated sodium chloride solution is used in liquid-liquid extractions. Can the mixture of benzoic acid, biphenyl, and benzocaine still be separated from one another if 5% hydrochloric acid is added at the beginning of the extraction instead of 5% sodium bicarbonate? Explain your answer 4.
Nestor RutherfordLv2
31 Jan 2019