CHEM 232 Final Exam Questions
and Answers 100% PASS
Consider the structure of the impure compound to be recrystallized. Is the
compound.... - CORRECT ANSWER-has some polar features
What type of solvent would be appropriate for recrystallization of this compound?
- CORRECT ANSWER-polar
Rank the solvents in order of increasing polarity - CORRECT ANSWER-hexane
acetone
ethanol
water
Solubility of ethanol - CORRECT ANSWER-soluble at high temperatures
insoluble at low temperatures
impurity - CORRECT ANSWER-recovery less than 100%
Which solvent would you use for recrystallizing (2 carboxylic acids and 3 benzene)
- CORRECT ANSWER-This compound is slightly polar so ethanol should be
used
,Water = too polar
Gravity Filtration - CORRECT ANSWER-used when the product of interest is in
the filtrate
Vacuum filtration - CORRECT ANSWER-leaves behind impurities
lower boiling point than literature - CORRECT ANSWER-indicates presence of
impurities
2-naphthol - CORRECT ANSWER-weak acid
Which reagent will convert 2-naphthol into an ionic compound - CORRECT
ANSWER-a strong base
3-Nitrobenzoic acid - CORRECT ANSWER-strong acid
Which reagent will convert 3-nitrobenzoic acid into a ionic compound -
CORRECT ANSWER-a weak base
1,4-dimethoxybenzene - CORRECT ANSWER-neutral
Which reagent will convert 1,4-dimethoxybenzene into an ionic compound -
CORRECT ANSWER-none; neutral
Which compound would be present in the aqueous layer after extraction with
sodium bicarbonate? - CORRECT ANSWER-3-nitrobenzoic acid
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, Which compound would be present in the aqueous layer after extraction with
sodium hydroxide? - CORRECT ANSWER-2-naphthol
Which compound would be present in the ether layer after 2 extractions? -
CORRECT ANSWER-1,4-dimethoxybenzene
Could we have performed the extraction experiment using acetone as the solvent
instead of diethyl ether as instructed in the procedure? - CORRECT ANSWER-
No. Acetone is miscible in water so it would not be possible to tell the difference
between the aqueous and organic layer
Supposed you were asked to separate acetanilide and 1,4-dimethoxybenzene using
liquid-liquid extraction if the two compounds were dissolved in dichloromethane.
Using HCl, or NaOH or NaHCO3, would you be able to separate the two solids? -
CORRECT ANSWER-No bc they are both neutral compounds
The stationary phase is.... (TLC) - CORRECT ANSWER-polar
The mobile phase is... (TLC) - CORRECT ANSWER-slightly polar
Chlorophyll-a - CORRECT ANSWER-blue pigment
slightly polar
Chlorophyll-b - CORRECT ANSWER-greenish yellow pigment
slightly polar
Xanthophyll - CORRECT ANSWER-yellow pigment
and Answers 100% PASS
Consider the structure of the impure compound to be recrystallized. Is the
compound.... - CORRECT ANSWER-has some polar features
What type of solvent would be appropriate for recrystallization of this compound?
- CORRECT ANSWER-polar
Rank the solvents in order of increasing polarity - CORRECT ANSWER-hexane
acetone
ethanol
water
Solubility of ethanol - CORRECT ANSWER-soluble at high temperatures
insoluble at low temperatures
impurity - CORRECT ANSWER-recovery less than 100%
Which solvent would you use for recrystallizing (2 carboxylic acids and 3 benzene)
- CORRECT ANSWER-This compound is slightly polar so ethanol should be
used
,Water = too polar
Gravity Filtration - CORRECT ANSWER-used when the product of interest is in
the filtrate
Vacuum filtration - CORRECT ANSWER-leaves behind impurities
lower boiling point than literature - CORRECT ANSWER-indicates presence of
impurities
2-naphthol - CORRECT ANSWER-weak acid
Which reagent will convert 2-naphthol into an ionic compound - CORRECT
ANSWER-a strong base
3-Nitrobenzoic acid - CORRECT ANSWER-strong acid
Which reagent will convert 3-nitrobenzoic acid into a ionic compound -
CORRECT ANSWER-a weak base
1,4-dimethoxybenzene - CORRECT ANSWER-neutral
Which reagent will convert 1,4-dimethoxybenzene into an ionic compound -
CORRECT ANSWER-none; neutral
Which compound would be present in the aqueous layer after extraction with
sodium bicarbonate? - CORRECT ANSWER-3-nitrobenzoic acid
COPYRIGHT ©️ 2025 ALL RIGHTS RESERVED
, Which compound would be present in the aqueous layer after extraction with
sodium hydroxide? - CORRECT ANSWER-2-naphthol
Which compound would be present in the ether layer after 2 extractions? -
CORRECT ANSWER-1,4-dimethoxybenzene
Could we have performed the extraction experiment using acetone as the solvent
instead of diethyl ether as instructed in the procedure? - CORRECT ANSWER-
No. Acetone is miscible in water so it would not be possible to tell the difference
between the aqueous and organic layer
Supposed you were asked to separate acetanilide and 1,4-dimethoxybenzene using
liquid-liquid extraction if the two compounds were dissolved in dichloromethane.
Using HCl, or NaOH or NaHCO3, would you be able to separate the two solids? -
CORRECT ANSWER-No bc they are both neutral compounds
The stationary phase is.... (TLC) - CORRECT ANSWER-polar
The mobile phase is... (TLC) - CORRECT ANSWER-slightly polar
Chlorophyll-a - CORRECT ANSWER-blue pigment
slightly polar
Chlorophyll-b - CORRECT ANSWER-greenish yellow pigment
slightly polar
Xanthophyll - CORRECT ANSWER-yellow pigment
