Recitation Problems for Exp. 3 Identifying a Constituent of \"Panacetin\" Name S
ID: 576714 • Letter: R
Question
Recitation Problems for Exp. 3 Identifying a Constituent of "Panacetin" Name Section Recitation problems may be collected randomly for a grade 1. Successful purification by recrystallization is based primarily on the solubility of a solute in a solvent. With the water solubility values given, which one or more of these solutes would recrystallize effectively in water? If not, identify the specific experimental issue you would encounter when recrystallizing. H2N 0.3g/100 mL 20 °C 24.99 g/100 mL 25 °C 0.2g/100 mL 20 °C 0.1g/100 mL 22 °C 0.0009 g/100 mL 25°C 2. Suggest 3 reasons why we employ water instead of ethanol as the recrystallization solvent for the unknowns? 3. Assuming you have 1.4 g of unknown recovered from Exp. 2, what are the minimum amounts of cold and hot water needed to dissolve that mass of both acetanilide and phenacetin? Why is phenacetin's water solubility different than that of acetanilide.Explanation / Answer
1. The selection of solvent for Recrystallization is the main step in the Recrystallization process .The primary condition for a solvent to be used for Recrystallization is that the solute must be insoluble in that solvent at room temperature(20-25°C) and soluble at higher temperatures (80-90°C).
Now out of the given compounds the last benzophenone having solubility .0009g/100mL at 25°C in water will be Recrystallized effectively because of its low solubility/insolubility at room temperature.
And the second one having solubility 24.99 g/100mL at 25°C can't be Recrystallized with water at all.
Other given compounds can be Recrystallized with water only if other solvents aren't available and the amount of compound is quite large as there will be the small loss of other compounds due to their solubility in water at room temperature.
Related Questions
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.