final

Question 1

Which is the best solvent of choice, water or ether; for TLC analysis of 2-bromooctane and 2-decene?

A. water
B. neither water nor ether
C. both water and ether
D. ether

Answer 1

D

Question 2

What can you conclude from a student who reported an Rf value of 1.2?

A. Distance traveled by sample was 1.2.
B. The ratio of distance traveled by sample to solvent was 1.2.
C. Distance traveled by solvent was 1.2.
D. The reported ratio is wrong, Rf value must be between 0 and 1

Answer 2

D

Question 3

What does an Rf value of 0 mean?

A. The ratio of distance traveled by sample to solvent was zero
B. Distance traveled by solvent was zero
C. Distance traveled by sample was zero
D. The ratio of distance traveled by solvent to sample was zero

Answer 3

A and C

Question 4

If two compounds have Rf values of 0.5 and 0.61, how far will they be separated from each other on the plate when the solvent is developed 12 cm?

A. 3.21 cm
B. 1.23 cm
C. 1.32 cm
D. 2.31 cm

Answer 4

C

Question 5

What can be used to visualize the TLC spots after development?

A. Use of UV light for those compounds absorbing the UV light
B. Use of x-ray light
C. Use of direct visualization for colored samples
D. Use of iodine to make it react with each sample

Answer 5

A, C, D

Question 6

How is an unknown sample identified using TLC?

A. By comparing the Rf value of unknown to those of known compounds
B. By comparing melting point of the sample to those of known compounds
C. By comparing solubility of the sample to those of known compounds
D. By comparing the color, shape, and distance traveled by sample to those of known compounds

Answer 6

A and D

Question 7

What is the purpose of performing a thin layer chromatography experiment?
A. To use TLC as a tool to determine purity of compounds separated by extraction
B. To identify aldehydes and ketones
C. To use TLC as a tool in identifying an unknown
D. To separate components of a mixture

Answer 7

A and C

Question 8

Arrange the following compounds in order of increasing Rf value if silica gel is used as an adsorbent and hexane is used as solvent:

A. CH3(CH2)10CH3
B. CH3(CH2)6OH
C. CH3(CH2)3COOH

Answer 8

1. C
2. B
3. A

Question 9

Which is the adsorbent of choice, alumina or silica gel; for TLC analysis of 2-bromooctane and 2-decene?

A. silica gel
B. alumina
C. both alumina and silica gel
D. neither alumina nor silica gel

Answer 9

B

Question 10

What would you expect to observe after plate development and visualization as a result of the following errors in the use of TLC? Match each error with its result.

A. If the solvent reaches the top of the TLC plate and is not stopped, then the distance traveled by solvent is not certain and, therefore, is not measurable

B. The sample will be washed down and will be dissolved away by the solvent.

C. If they are spotted too close together, will tend to spread out and run together as they are

1. The solvent level in the developing
   chamber is higher than the spotted
   sample.
2. Too much sample is applied to the
   The TLC plate
3. The TLC plate is allowed to remain in the developing chamber after the solvent has reached the top.

Answer 10

A) 3
B) 1
C) 2

Question 11

True or False? Claisen adapter prevents the foam from heated plant materials from making it to distillation head/condenser in steam distillation

Answer 11

true

Question 12

Which of the following statements are correct?

A) In a distillation of two immiscible liquids, the number of moles of each component in the vapor is proportional to the vapor pressure of the pure component.
B) Boiling point of the mixture of water and eugenol is less than the boiling point of water and boiling point of eugenol.
C) In a distillation of water and eugenol, the number of moles of eugenol in the vapor and/or distillate is much higher than the number of moles of water.
D) In a distillation of water and eugenol, the number of moles of water in the vapor and/or distillate is much higher than the number of moles of eugenol.

Answer 12

A B D

Question 13

Why is eugenol steam-distilled rather than purified by simple distillation?

A) Eugenol will not be exposed to high temperature, therefore will not be decomposed.
B) The difference in boiling point of water and eugenol is too close to do simple distillation.
C) The mixture of water and eugenol will boil at a temperature less than 100°C.
D) Water and eugenol are not miscible, so we cannot use fractional distillation.

Answer 13

A and C

Question 14

Which of the following statements are correct?
A) The boiling point of a mixture of two miscible liquids will be between the boiling point of compound with lower boiling point and the boiling point of the compound with high boiling point.
B) When a mixture of two miscible liquids is heated or distilled, the total vapor pressure is the sum of the partial vapor pressures of the components.
C) When a mixture of two immiscible liquids is heated or distilled, the total vapor pressure is the sum of the vapor pressures of the pure individual components.
D) The boiling point of a mixture of two immiscible liquids will be between the boiling point of compound with lower boiling point and the boiling point of the compound with high boiling point

Answer 14

A B C

Question 15

When would you stop the heat for steam distillation?

A) The distillate was milky and the dripping distillate from the vacuum adapter is clear
B) The recommended time for distillation is finished
C) The boiling flask is almost dry and there is no water left in the separatory funnel to replenish the water
D) The recommended quantity of distillate is collected

Answer 15

A C D

Question 16

True or False? To remove water/moisture from the methylene chloride solution add 1 spoon of calcium chloride pellets.

Answer 16

False

Question 17

What is the purpose of performing Steam Distillation experiment?

A) To extract temperature-sensitive organic natural products from plant materials.
B) To separate components of a mixture
C) To extract water immiscible organic natural products from plant materials.
D) To learn about the theoretical aspects involved in the steam distillation process.

Answer 17

A C D

Question 18

True or False? The newly condensed steam distillate of eugenol appears cloudy because water and eugenol are misible.

Answer 18

false

Question 19

What classical chemical methods are used to test the functional groups of the eugenol?

A) Test for unsaturation using 2% KM04 solution
B) Test for phenol functional group using ferric chloride solution
C) Test for phenol functional group using chromic acid solution
D) Test for aldehyde functional group using chromic acid solution

Answer 19

A and B

Question 20

What are some of the differences between steam distillation, fractional distillation, simple distillation from an apparatus, and theoretical perspective?

A) Fractional distillation apparatus contains fractionating column added to simple distillation apparatus.
B) Steam distillation is used only for water misible compounds.
C) Fractional distillation is used for misible mixture of liquids with 20° difference in boiling point or higher.
D) Simple distillation is used only for misible mixture of liquids with 80° difference in boiling

Answer 20

A C D

Question 21

True or False? The (R)-amine: (R, R)-tartaric acid salt is more soluble in methanol than the (S) -amine: (R, R) - tartaric acid salt.

Answer 21

true

Question 22

What factors affect the specific rotation of the product

A) Path length in decimeter
B) Temperature of the sample
C) Mass/concentration of product g/mL
D) Measured rotation in degrees

Answer 22

all

Question 23

Which of the following statements are correct?

A) An equimolar mixture of two enantiomers is known as a racemic mixture or racemate.
B) Diastereomer are mirror images of one another.
C) When a 1:1 ratio of enantiomers of 1-phenylethylamine is reacted with a single enantiomer of tartaric acid two diastereomeric salts form.
D) Enantiomers have identical physical properties (e.g. melting point, boiling point, and solubility in methanol).

Answer 23

A C D

Question 24

Which of the following statements are correct?

A) Samples that rotate polarized light are said to be optically active.
B) Prismatic crystals will produce the highest ee%.
C) Diastereomers (generally) have different physical properties.
D) Enantiomers do not interact with plane-polarized light in the same way.

Answer 24

all

Question 25

In this experiment, if student obtains an amine with [a]^20 D =-35.3°, what is the optical purity of the amine? (Note: Use [a]20 D = -40.3° as the literature value.) A) 87.5% B) 90% C) 85% D) 93.75%

Answer 25

A

Question 26

True or False? A refractometer is used to determine the optical rotation of the product.

Answer 26

false

Question 27

True or False? Needle-like crystals will produce the lowest ee%.

Answer 27

true

Question 28

True or False? A racemic mixture rotates plane-polarized light.

Answer 28

false l

Question 29

What is the purpose of performing Resolution of 1-Phenylethylamine experiment? A) To determine the optical rotation of the product B) To isolate (S)-(-)-1-phenylethylamine from Racemic (1) - phenylethylamine C) To learn how to use polarimeter D) To determine enantiomeric excess and evaluate the efficiency of our resolution

Answer 29

all

Question 30

What is the purpose of using each of the following solutions in this experiment? Match each solution to its purpose. __ To absorb traces of moisture from the organic layer __To remove traces of water from organic layer or to help the two layers to form __ To recover the free amine from the ammonium salt 1. Adding 10% NaOH solution to the prismatic crystals 2. Adding NaCI to the content of separatory funnel 3.Adding a full spatula of anhydrous potassium carbonate to the organic layer after is transferred to a beaker

Answer 30

3 2 1

Question 31

What is the purpose of performing Synthesis of Cyclohexene experiment? A) To identify the organic phase in an immiscible organic/aqueous mixture B) To learn how to wash and dry an organic solid C) To set up a distillation apparatus and perform a distillation D) To learn how to measure refractive index as a tool to determine the purity of liquids

Answer 31

A C D

Question 32

Which of the following statements are correct? A) The substitution product is also a possible side product B) Formation of carbocation is the slow step of reaction in dehydration of alcohol C) The elimination reaction of an alcohol often yields a major and minor alkene product D) The rate of dehydration reaction is fastest for 3° alcohols

Answer 32

all

Question 33

List the following alcohols in order of increasing reactivity (least reactive first) toward dehydration with concentrated sulfuric acid. CH3CH2OH (CH3CH2)3СОН СHзСНОНСНз

Answer 33

1 3 2

Question 34

What classical chemical methods are used to test the functional groups of the product? A) Test for unsaturation using 2% KMnO4 solution B) Test for aldehyde functional group using chromic acid solution C) Test for unsaturation using bromine/dichloromethane solution D) Test for phenol functional group using ferric chloride solution

Answer 34

A and C

Question 35

What is the purpose of using each of the following solutions in the separatory funnel. Match each solution to its purpose. To remove traces of acid from organic layer To absorb traces of moisture from the organic layer To remove all water-soluble impurities from organic layer/product 1. Adding 20 mL of water after transfering the distillate to a separatory funnel 2. Washing the organic layer with 10 mL of 10% sodium carbonate solution 3. Adding a full spatula of calcium chloride pellets to the organic layer after is transferred to an erlenmeyer flask

Answer 35

2 3 1

Question 36

Which of the following statements are correct? A) An elimination reaction of an alcohol is a dehydration reaction B) An elimination reaction of an alcohol yields the most stable (highly substituted) alkene as major product C) An elimination reaction of an alcohol is an exothermic reaction D) An elimination reaction of an alcohol yields an alkene and water

Answer 36

A B D

Question 37

How many alkene products can form from the following reaction? OH | H+ (CH3CH2)2CCH3 ----> A) 1 B) 3 C) not possible D) 2

Answer 37

D

Question 38

True or False? When 2-methylcyclohexanol is dehydrated with H2SO4/H3PO4, two alkene product will form

Answer 38

true

Question 39

How many alkene products can form from the following reaction, including rearranged products? OH | H+ 🛑🛑 ------> A) not possible B) 3 C)2 D)1

Answer 39

B

Question 40

Why is it important to surround the receiving flask with an ice-water bath? A) To slow down the reaction rate at low temperature B) To help with condensation of the vapor C) To avoid vaporization of the distillate due to low boiling point D) To make sure crystallization is complete

Answer 40

B C

Question 41

What is the purpose of using each of the following after the reaction is done in separatory funnel? Match each action with its purpose. ____To absorb traces of moisture from the organic layer ____To remove traces of acid from organic layer ____To remove all water-soluble impurities from organic layer/product 1. Washing the alkyl halide with 10 mL of cold water to the separatory funnel 2. Washing the organic layer with 10 mL of 10% sodium carbonate solution 3. Adding a full spatula of calcium chloride pellets to the organic layer after is transferred to an erlenmeyer flask

Answer 41

3 2 1

Question 42

Why is it important to cool the 12M HCI solution in ice-bath for 5 to 10 minutes in fume hood? A) To increase formation of desired substitution product B) To remove heat which favors formation of elimination product C) To avoid vaporization of the HCI solution D) To make sure crystallization is complete

Answer 42

A B

Question 43

Which of the following statements are correct? A) Formation of carbocation is the slow step of reaction in SN1 B) Hydroxide ion is not a good leaving group, but it can be activated by protonation C) Strength of nucleophile does not affect the rate of the Sy1 reactions D) Good leaving group speeds up both Sn2 reaction and SN/1 reaction

Answer 43

all

Question 44

List the following alcohols in order of increasing reactivity (least reactive first) toward Sn2 reaction to form an alkyl halide with HBr. (CH3CH2)3 COH CH3CHOHCH3 CH3CH2OH

Answer 44

1 2 3

Question 45

What are the purposes of using hydrochloric acid (HCI) in the reaction of t-butyl alcohol? A) HCI functions as a good leaving group B) HCI is used as polar solvent C) HCI is used as the acid catalyst to protonate the tertiary alcohol D) HCl provides the nucleophile of Cl

Answer 45

C D

Question 46

If 10.0 grams of t-butyl alcohol reacts excess of hydrochloric acid, calculate the theoretical yield in grams of t-butyl chloride. A) 15g B) 10g C) 12.5g D) 7.5g

Answer 46

C

Question 47

True or False? The product of t-butyl chloride is less dense than water and is not soluble in water.

Answer 47

true

Question 48

Which of the following statements are correct? A) The concentrations of both the alkyl halide and the nucleophile are affecting the observed rate for SN2 reaction B) A bimolecular reaction of alkyl halides is called SN2 reaction C) The concentration of only one reactant, the alkyl halide, is affecting the observed rate for Sn1 reaction D) A reaction with Sn1 mechanism would be faster with tertiary alkyl halides

Answer 48

all

Question 49

What classical chemical tests or physical properties are used to test the functional group of the product? A) Silver nitrate test for presence of the tertiary alkyl halide B) Refractive index as a tool to determine the purity/identity of the product C) Test for unsaturation using bromine/dichloromethane solution D)Test for aldehyde functional group using chromic acid solution

Answer 49

A B

Question 50

What is the purpose of performing Synthesis of Alkyl chloride experiment? A) To convert tertiary alcohol into an alkyl halide by reacting it with hydrochloric acid B) To learn how to wash and dry an organic solid C) To learn how to measure refractive index as a tool to determine the purity of liquids D) To test the presence of the tertiary alkyl halide using the silver nitrate test

Answer 50

A C D