CHEM 219 MODULES 1–8 EXAMS &
FINAL EXAM – PRINCIPLES OF
ORGANIC CHEMISTRY (2026/2027) |
PORTAGE LEARNING – VERIFIED Q&A
1. Explain how the solubility of compounds changes during acid-base
extraction and why this is significant for separation.
The solubility remains constant, making separation ineffective.
The solubility of compounds increases in organic solvents, allowing
for easier extraction.
The solubility of compounds changes based on their protonation
state, which is crucial for effective separation.
The solubility of compounds decreases in aqueous solutions,
complicating the extraction process.
2. Explain why stoichiometry is essential for calculating theoretical yield in
chemical reactions.
It helps determine the cost of reactants.
It provides a method to measure the temperature of the reaction.
It allows for the prediction of product formation based on
reactant ratios.
It is used to analyze the color change during a reaction.
3. What is the effect of electron donating groups (EDGs) on the reactivity of
the aromatic ring in Friedel-Craft reactions?
They deactivate the ring and direct substituents to meta positions
,They activate the ring and direct substituents to ortho/para
positions
They have no effect on the ring
They only affect the yield of the reaction
,4. Thin Layer Chromatography (TLC) is useful in the organic laboratory to:
Identify components in a mixture
Assess the purity of a sample
Monitor reactions & purifications
All of the above
5. What is the main principle that allows distillation to effectively separate
components in a mixture?
Differences in solubility
Differences in boiling points
Differences in molecular weight
Differences in density
6. If a chemist needs to concentrate a solution of a volatile solvent that has a
boiling point of 78°C, which laboratory technique would be most effective,
and why?
Recrystallization, because it purifies solids
Distillation, because it separates components based on boiling
points
Rotary evaporation, because it lowers the boiling point through
reduced pressure
Thin layer chromatography, because it separates based on polarity
7. What is the primary effect of larger substituents on the position of
substitution in Friedel-Craft alkylation reactions?
They promote ortho substitution.
They have no effect on substitution position.
They hinder ortho substitution and favor para substitution.
, They only affect the reaction rate.
8. Name of mechanism of acid-catalyzed dehydration of cyclohexanol?
SN1
SN2
E1
E2
E1cB
9. What is the typical wavenumber range for the IR peak associated with an
alcohol (O-H) functional group?
3200-3600 cm-1
1700-1750 cm-1
2100-2300 cm-1
1500-1600 cm-1
10. If a mixture contains two liquids with boiling points of 60°C and 80°C, how
would you set up a distillation to maximize the separation of these
components?
Use a distillation apparatus with a heating rate that exceeds 80°C.
Gradually increase the temperature starting from 60°C to 80°C
to collect both components.
Maintain a constant temperature of 70°C throughout the distillation.
Start the distillation at 80°C and then lower the temperature to
60°C.
11. What is the primary purpose of using a rotary evaporator in laboratory
settings?
FINAL EXAM – PRINCIPLES OF
ORGANIC CHEMISTRY (2026/2027) |
PORTAGE LEARNING – VERIFIED Q&A
1. Explain how the solubility of compounds changes during acid-base
extraction and why this is significant for separation.
The solubility remains constant, making separation ineffective.
The solubility of compounds increases in organic solvents, allowing
for easier extraction.
The solubility of compounds changes based on their protonation
state, which is crucial for effective separation.
The solubility of compounds decreases in aqueous solutions,
complicating the extraction process.
2. Explain why stoichiometry is essential for calculating theoretical yield in
chemical reactions.
It helps determine the cost of reactants.
It provides a method to measure the temperature of the reaction.
It allows for the prediction of product formation based on
reactant ratios.
It is used to analyze the color change during a reaction.
3. What is the effect of electron donating groups (EDGs) on the reactivity of
the aromatic ring in Friedel-Craft reactions?
They deactivate the ring and direct substituents to meta positions
,They activate the ring and direct substituents to ortho/para
positions
They have no effect on the ring
They only affect the yield of the reaction
,4. Thin Layer Chromatography (TLC) is useful in the organic laboratory to:
Identify components in a mixture
Assess the purity of a sample
Monitor reactions & purifications
All of the above
5. What is the main principle that allows distillation to effectively separate
components in a mixture?
Differences in solubility
Differences in boiling points
Differences in molecular weight
Differences in density
6. If a chemist needs to concentrate a solution of a volatile solvent that has a
boiling point of 78°C, which laboratory technique would be most effective,
and why?
Recrystallization, because it purifies solids
Distillation, because it separates components based on boiling
points
Rotary evaporation, because it lowers the boiling point through
reduced pressure
Thin layer chromatography, because it separates based on polarity
7. What is the primary effect of larger substituents on the position of
substitution in Friedel-Craft alkylation reactions?
They promote ortho substitution.
They have no effect on substitution position.
They hinder ortho substitution and favor para substitution.
, They only affect the reaction rate.
8. Name of mechanism of acid-catalyzed dehydration of cyclohexanol?
SN1
SN2
E1
E2
E1cB
9. What is the typical wavenumber range for the IR peak associated with an
alcohol (O-H) functional group?
3200-3600 cm-1
1700-1750 cm-1
2100-2300 cm-1
1500-1600 cm-1
10. If a mixture contains two liquids with boiling points of 60°C and 80°C, how
would you set up a distillation to maximize the separation of these
components?
Use a distillation apparatus with a heating rate that exceeds 80°C.
Gradually increase the temperature starting from 60°C to 80°C
to collect both components.
Maintain a constant temperature of 70°C throughout the distillation.
Start the distillation at 80°C and then lower the temperature to
60°C.
11. What is the primary purpose of using a rotary evaporator in laboratory
settings?
