15. Artange the folowing based on INCREASING melting point 40mg of the sample wa

Question

15. Artange the folowing based on INCREASING melting point 40mg of the sample was recrystaliced at 30'C using 50mL of the chosen solvent If the sample was recrystalled torn a satnted sauson at 70°C with a0% tecovery, what is se soublity at the sample at 30°C? Assume hat the impurtes ane negi gbe in mass C. 064 mgml 8. Which of the folowing anagesics will have the highest R in reverse phase chromatography A aspirin C. ibuprofen The diagram below shows the temperature-composition dlagram of chloroferm-mathanol at ambient Why must the solvend front alwaya start beneath he spots on the statonary phase? A To ensure that the distance traviled by he solvent front is maximiced B. To prevont taling from occuing C To alow the solute spos to athere to the stationary phase D. To prevent the dissolution of the solutes Temperature tinimum Aeorepe Mixture of Chioraform and Methanoll Aze Q. Allen wants to isolate calfeine from tea leaves. The tea leaves was toiled in hat water. Ater cooling the water extract, IquidlSid ?eaction wth DCM was used to etact wnns tpolyphenole compounds in tea leaves) and cafone. Which solvent could be used to remove the tannins fom the DCM sdlvent? Pure boiing point P 101 325 kPa 3of Methanol 6 M NaOH D. hesane Pure boiling point of Chlorofom 11, In he analysis of erld content of a topical ceam, iquis-iqud etraction with dechyl eher was used to extrac the steroid. Pipau atserved tha! venting the separatory unnel is usualy more vicient when disthyl ether is the extracing salvent compared to hexane. Which of the folowing accounts for Phis abservation? A The solute partions less into diethyl ether than into hexane. B. The Ko of the solute is much lower in diethyl ether than in hexane. C. Diethyl erer more volatie compared to hexane D. The boiing point of ether is much higher than hexane 12. The EIOvweter motu" ? Dostve azeotrope which orthe blowing statemet is he? 2a 27 325 L The boling point of the anectrope is lower than pute EO The boling point of the anectrope is higher an pure ExcH There is a more faverable intaracson betwean EtOH and water mclecules like molecules of EIOH leads to n he vapor pressure Addtion of ttoleads to a decrease in the vapor pressure VM 13. Substance E has a boiling point 72 C while substance H has a boiling point of 79c. which of the following dstilaion techniques wouid be best for the seperation of a mixture of the two liquios? A Fractional Dstlasion B Vacuum Distilation B What is the composton of the azeotrope7 C. What is the boiling point of the azeotrope? D. What is the compoaiton of the Srst drop of the distlate with 0.50 E. At what temperature will the first drop of the disslate in leter D will occur? D. Any of the aforementioned techniques 4. Arrange the folowing liquid based on INCREASING Boling point

Explanation / Answer

Ans 7

At 30°C

Mass of sample = 40 mg

Volume of solvent = 50 mL

At 70 °C

Saturated solution

80% of 40 mg recovered

Mass of pure sample = 0.80*40 = 32 mg

Mass of sample in solvent = 40 - 32 = 8 mg

Solubility = 8 mg / 50 mL

= 0.16 mg/mL

Option A is the correct answer

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