CHEM 232 Final Exam Questions and Answers Already Passed Latest Update 2025-2026
Consider the structure of the impure compound to be recrystallized. Is the compound.... -
Answers has some polar features
What type of solvent would be appropriate for recrystallization of this compound? - Answers
polar
Rank the solvents in order of increasing polarity - Answers hexane
acetone
ethanol
water
Solubility of ethanol - Answers soluble at high temperatures
insoluble at low temperatures
impurity - Answers recovery less than 100%
Which solvent would you use for recrystallizing (2 carboxylic acids and 3 benzene) - Answers
This compound is slightly polar so ethanol should be used
Water = too polar
Gravity Filtration - Answers used when the product of interest is in the filtrate
Vacuum filtration - Answers leaves behind impurities
lower boiling point than literature - Answers indicates presence of impurities
2-naphthol - Answers weak acid
Which reagent will convert 2-naphthol into an ionic compound - Answers a strong base
3-Nitrobenzoic acid - Answers strong acid
Which reagent will convert 3-nitrobenzoic acid into a ionic compound - Answers a weak base
1,4-dimethoxybenzene - Answers neutral
Which reagent will convert 1,4-dimethoxybenzene into an ionic compound - Answers none;
neutral
, Which compound would be present in the aqueous layer after extraction with sodium
bicarbonate? - Answers 3-nitrobenzoic acid
Which compound would be present in the aqueous layer after extraction with sodium hydroxide?
- Answers 2-naphthol
Which compound would be present in the ether layer after 2 extractions? - Answers 1,4-
dimethoxybenzene
Could we have performed the extraction experiment using acetone as the solvent instead of
diethyl ether as instructed in the procedure? - Answers 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? - Answers No bc they are both neutral
compounds
The stationary phase is.... (TLC) - Answers polar
The mobile phase is... (TLC) - Answers slightly polar
Chlorophyll-a - Answers blue pigment
slightly polar
Chlorophyll-b - Answers greenish yellow pigment
slightly polar
Xanthophyll - Answers yellow pigment
polar
carotene - Answers orangish yellow pigment
non polar
order of pigments on TLC plate (least to greatest distance traveled - Answers xanthophyll
chlorophyll-b
chlorophyll
carotene
compounds from extraction on TLC plate (least to greatest distance travelled) - Answers 3-nitro
2-naphthol
Consider the structure of the impure compound to be recrystallized. Is the compound.... -
Answers has some polar features
What type of solvent would be appropriate for recrystallization of this compound? - Answers
polar
Rank the solvents in order of increasing polarity - Answers hexane
acetone
ethanol
water
Solubility of ethanol - Answers soluble at high temperatures
insoluble at low temperatures
impurity - Answers recovery less than 100%
Which solvent would you use for recrystallizing (2 carboxylic acids and 3 benzene) - Answers
This compound is slightly polar so ethanol should be used
Water = too polar
Gravity Filtration - Answers used when the product of interest is in the filtrate
Vacuum filtration - Answers leaves behind impurities
lower boiling point than literature - Answers indicates presence of impurities
2-naphthol - Answers weak acid
Which reagent will convert 2-naphthol into an ionic compound - Answers a strong base
3-Nitrobenzoic acid - Answers strong acid
Which reagent will convert 3-nitrobenzoic acid into a ionic compound - Answers a weak base
1,4-dimethoxybenzene - Answers neutral
Which reagent will convert 1,4-dimethoxybenzene into an ionic compound - Answers none;
neutral
, Which compound would be present in the aqueous layer after extraction with sodium
bicarbonate? - Answers 3-nitrobenzoic acid
Which compound would be present in the aqueous layer after extraction with sodium hydroxide?
- Answers 2-naphthol
Which compound would be present in the ether layer after 2 extractions? - Answers 1,4-
dimethoxybenzene
Could we have performed the extraction experiment using acetone as the solvent instead of
diethyl ether as instructed in the procedure? - Answers 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? - Answers No bc they are both neutral
compounds
The stationary phase is.... (TLC) - Answers polar
The mobile phase is... (TLC) - Answers slightly polar
Chlorophyll-a - Answers blue pigment
slightly polar
Chlorophyll-b - Answers greenish yellow pigment
slightly polar
Xanthophyll - Answers yellow pigment
polar
carotene - Answers orangish yellow pigment
non polar
order of pigments on TLC plate (least to greatest distance traveled - Answers xanthophyll
chlorophyll-b
chlorophyll
carotene
compounds from extraction on TLC plate (least to greatest distance travelled) - Answers 3-nitro
2-naphthol
