CHEM 232L Final Exam with Accurate
Solutions
What is the purpose of recrystallization?
A. Purify solids
B. Purify liquids
C. Purify gases
D. Helps separate layers during extraction - ANSWER-A. Purify solids
What is the purpose of heating up the solvents for recrystallization?
A. To increase solubility
B. To melt the solids
C. To separate the impurities
D. To allow the growth of beautiful crystals - ANSWER-A. To increase solubility
What is the phenomenon of reduction of the melting point of a compound caused by the
presence of impurities?
A. Decreased Solubility
B. Liquification Deduction
C. Freezing Point Happiness
D. Melting Point Depression - ANSWER-D. Melting Point Depression
What should you do if too much solvent has been used and crystals do not form when
the solution is cooled?
A. Boil off the solvent to re-saturate the solution
B. Give up and go home
C. Add more solvent
D. Freeze the solvent to induce crystallization - ANSWER-A. Boil off the solvent to re-
saturate the solution
What is the primary solvent used in the extraction of the active ingredient from an
analgesic
drug in the described procedure?
A) Ethanol
B) Acetone
, C) Methanol
D) Water - ANSWER-D) Water
Which technique is employed to separate fine particles of binder from the active
ingredient
after dissolution?
A) Filtration
B) Centrifugation
C) Distillation
D) Sublimation - ANSWER-A) Filtration
Which of the following steps is NOT part of the procedure for extracting the active
ingredient
from the analgesic drug?
A) Crushing the tablet
B) Dissolving in methanol
C) Adding hydrochloric acid
D) Centrifugation - ANSWER-D) Centrifugation
What is the significance of using a Hirsch funnel in the procedure?
A) To measure the melting point
B) To dry the active ingredient crystals
C) To mix the solution thoroughly
D) To weigh the extracted substance - ANSWER-B) To dry the active ingredient crystals
Which observation is NOT considered the start of the melting point range during the
analysis?
A) The solid takes on a shiny appearance
B) The solid begins to shrink
C) The first drop of liquid is observed
D) The solid becomes slightly wet - ANSWER-D) The solid becomes slightly wet
Why is it important to complete the evaporation procedure within 10-15 minutes?
A) To prevent the methanol from freezing
B) To avoid decomposition of the drug
C) To ensure all binder is removed
D) To maintain a constant temperature - ANSWER-B) To avoid decomposition of the
drug
If the liquid collected after column chromatography is still cloudy, what should be done?
A) Add more methanol to the column
Solutions
What is the purpose of recrystallization?
A. Purify solids
B. Purify liquids
C. Purify gases
D. Helps separate layers during extraction - ANSWER-A. Purify solids
What is the purpose of heating up the solvents for recrystallization?
A. To increase solubility
B. To melt the solids
C. To separate the impurities
D. To allow the growth of beautiful crystals - ANSWER-A. To increase solubility
What is the phenomenon of reduction of the melting point of a compound caused by the
presence of impurities?
A. Decreased Solubility
B. Liquification Deduction
C. Freezing Point Happiness
D. Melting Point Depression - ANSWER-D. Melting Point Depression
What should you do if too much solvent has been used and crystals do not form when
the solution is cooled?
A. Boil off the solvent to re-saturate the solution
B. Give up and go home
C. Add more solvent
D. Freeze the solvent to induce crystallization - ANSWER-A. Boil off the solvent to re-
saturate the solution
What is the primary solvent used in the extraction of the active ingredient from an
analgesic
drug in the described procedure?
A) Ethanol
B) Acetone
, C) Methanol
D) Water - ANSWER-D) Water
Which technique is employed to separate fine particles of binder from the active
ingredient
after dissolution?
A) Filtration
B) Centrifugation
C) Distillation
D) Sublimation - ANSWER-A) Filtration
Which of the following steps is NOT part of the procedure for extracting the active
ingredient
from the analgesic drug?
A) Crushing the tablet
B) Dissolving in methanol
C) Adding hydrochloric acid
D) Centrifugation - ANSWER-D) Centrifugation
What is the significance of using a Hirsch funnel in the procedure?
A) To measure the melting point
B) To dry the active ingredient crystals
C) To mix the solution thoroughly
D) To weigh the extracted substance - ANSWER-B) To dry the active ingredient crystals
Which observation is NOT considered the start of the melting point range during the
analysis?
A) The solid takes on a shiny appearance
B) The solid begins to shrink
C) The first drop of liquid is observed
D) The solid becomes slightly wet - ANSWER-D) The solid becomes slightly wet
Why is it important to complete the evaporation procedure within 10-15 minutes?
A) To prevent the methanol from freezing
B) To avoid decomposition of the drug
C) To ensure all binder is removed
D) To maintain a constant temperature - ANSWER-B) To avoid decomposition of the
drug
If the liquid collected after column chromatography is still cloudy, what should be done?
A) Add more methanol to the column
