238 finial exam

Organic Chemistry Laboratory Final Exam Chemistry 238Exam Version A Spring 2011

Chemistry 238 Exam Version A Page 3 of 14

Choose the most correct answer: (4 points each)

_____ 1. A To prepare 4-methyl-3-hexanol from a Grignard reaction, you need to use which startingmaterials?a. 2-bromobutane and propanalb. 2-bromopentane and acetaldehydec. methyl bromide and 2-pentanoned. 2-bromopentane and propanale. 1-bromopropane and 2-butanone

_____ 2. B In the UV-VIS spectra, if the λmax for CH2=CHCH=CH2 is 300nm, what would you expect theλmax for CH2=CH2 to be:a. > 300 nmb. < 300 nm

c. = 300 nmd. 150 nm

e. none of these

_____ 3. A The ceric nitrate test is used to detect the presence of ________a. alcoholsb. carboxylic acids

c. amides d. aldehydes

e. amino acids

_____ 4. B In the reaction of sodium borohydride with camphor, a. the endo alcohol is the main product because steric hindrance limits

the exo approach of the borohydride.b. the exo alcohol is the main product because steric hindrance limits

the exo approach of the borohydride.c. ring opening occurs due to the steric influence of the methyl groups.d. the exo alcohol is the main product because steric hindrance limits

the endo approach of the borohydride.e. the camphor is reduced to an alkane

_____ 5. B What type of mechanism is observed for the following reaction?

a. electrophilic aromatic substitutionb. nucleophilic aromatic substitutionc. E2 eliminationd. SN2 substitutione. SN1 substitution

_____ 6. C Which test would be positive for the following compound: CHCH2CCH3

O

CH3CHI. Iodoform test II. Schiff’s test III. Baeyer

IV. Copper Acetylide V. Bromine

a. I and IIIb. III and IV

c. I, III and Vd. II and IV

e. all five

H3C CH3

OCH3

N

N

N

Cl

Cl ClNH2

4 N

N

N

Cl

HN NH

NH3 Cl

Chemistry 238 Organic Chemistry Laboratory Final ExamSpring 2011 Exam Version A

Page 4 of 14 Exam Version A Chemistry 238

_____ 7. C An intermediate in the Fischer esterification of benzoic acid and methanol is:

a. C

O

b. C

O

O

HH

CH3

c. C

O

O

HH

CH3OH

d. C

O

O

H

CH3

e. C

O

O CH3

_____ 8. C Complete hydrolysis of aspartame gives:a. water, alanine and glutamic acidb. water, glutamic acid and phenylalaninec. methanol, aspartic acid and phenylalanined. methanol, alanine and lysinee. all of these

_____ 9. C The type of UV light that one might receive on a sunny day that gives rise to immediatesunburn is:a. UVCb. UVB

c. UVAd. a and b

e. a and c

_____ 10. D Which pair of compounds would react to give one major product through an aldolcondensation reaction upon the slow addition of the two compounds to a basic solution?

a. CH3CH2C H

O+ CH3CH2OCH3

b. CH3CH2C CH3

O+ CH3C H

O

c. CH3CH2C H

O

+ CH3C H

O

d.H

O

O+

e.O O

+



1

23

4

5

_____ 11. D Which of the following compounds can be reduced by sodium borohydride?

a. CH3CO2H

b. CH3CO2CH3

c.

O

CH3C NH2

d.

O

CH3C CH3

e. CH3CH2OH

_____ 12. E For the following allylic cation, the positive charge will be distributedon _______.a. only on C1b. on C2 and C3c. on C3 and C5

d. only on C3e. on C1 and C3

_____ 13. B A carbonyl compound gave a positive silver mirror test with Tollens' reagent. It also gave ayellow precipitate in the iodoform test. The compound is most likely:a. 2-propanoneb. acetaldehydec. phenyl acetaldehyde

d. benzaldehydee. cyclohexanone

_____ 14. E E When benzylamine is treated with an excess of methyl iodide, product is:

a. CH2NH2

b. CH2NC(CH3)2

c. CH2N(I)2

d. CH2NHCH3

e. CH2N(CH3)3I+ _

_____ 15. A Amides can be prepared by reacting an amine witha. an acid chlorideb. a carboxylic acidc. an aldehyde

d. a bromohydrine. an alcohol

_____ 16. B In order to determine whether the desired product type was produced in the GrignardReaction, you obtained an IR spectrum. The main peak looked for was at approximately: a. 2400-2580 cm-1

b. 3200-3600 cm-1

c. 1700-1720 cm-1

d. 3010-3100 cm-1

e. Fingerprint Region



_____ 17. B In the Eschweiler-Clarke reaction, a primary amine reacts with formaldehyde to give animine. This imine is then reduced by ______ to give a secondary amine.a. proton transfer from HCO2Hb. hydride transfer from HCO2

– c. evolution of CO2

d. benzylaminee. an immonium ion

_____ 18. C A compound forms a 2,4-dinitrophenylhydrazine derivative, gives a positive iodoform testand a negative result for both the Tollens' and Schiff's tests. This compound is most likely:

a.

O

CH3CH2CCH(CH3)2

b.

O

CH3CH

c.

O

CH3CH2CCH3

d. O

e. OH

_____ 19. C Only one major product is observed in the nitration of methyl benzoate. This is due to:a. the increased reactivity of the meta position compared to benzeneb. strong steric effects at the para positionc. the relatively low reactivity of the ortho and para positionsd. the activating influence of the methyl ester groupe. the low temperature at which the reaction is conducted

_____ 20. D The ester, butyl 2-methylbutanoate, is made by reaction of ________ in the presence of anacid catalyst.

a. COH OH

O

+

b. COH OH

HO O+

c. COH OH

O

+

d. COH OH

O

+

e. COH

OHO

+



O

C(CH3)2CH CH3 + ?CH3CH2CH2MgBrether H2O, H+

_____ 21. D What is the product of the following reaction?

a.

OH

C(CH3)2CH

CH3

CH(CH3)2

b.

O

C(CH3)2CH CH2CH2CH3

c.

OH

C(CH3)2CH CH2CH2CH3

CH2CH2CH3

d.

OH

C(CH3)2CH CH2CH2CH3

CH3

e.

OH

C(CH3)2CH CH2CH2CH3

CH(CH3)2

_____ 22. D Which is the best solvent choice for TLC of a three compound mixture of A, B, and C?Rf of A Rf of B Rf of C

a. 10% ethyl acetate 90% hexane

0.12 0.07 0.01

b. 20% ethyl acetate 80% hexane

0.34 0.29 0.05

c. 30% ethyl acetate 70% hexane

0.53 0.45 0.10

d. 40% ethyl acetate 60% hexane

0.72 0.61 0.25

e. 50% ethyl acetate 50% hexane

1.0 0.8 0.7

_____ 23. E When the observed product ratio is controlled by the relative stabilities of the products andnot the relative energies of the transition states leading to the two products, this type ofproduct ratio control is known asa. nucleophilicb. kineticc. electric

d. dynamice. thermodynamic



N

N

N

Cl

ClCl

N

N

N

NH

NHHN

NH2

+ n

_____ 24. E Which of the following reagents would you use to prepare an intermediate for the synthesisof benzamide?a. benzene and benzylamine (C6H5CH2NH2)b. benzene and ammonia (NH3)c. benzoic acid and benzyl chloride (C6H5CH2Cl)d. benzoyl chloride (C6H5COCl) and methanol (CH3OH)e. benzoic acid and thionyl chloride (SOCl2)

_____ 25. A Proteins are made of strings of amino acids joined by peptide bonds. What is another termfor a peptide bond?a. amide bondb. ester bondc. ether bondd. amine bonde. hydrazine bond

_____ 26. A Arrange the following in order of decreasing reactivity towards the reaction with nitroniumion. (most reactive to least reactive)a. benzene > methyl benzoate > methyl m-nitrobenzoateb. methyl benzoate > methyl m-nitrobenzoate > benzenec. methyl m-nitrobenzoate > methyl benzoate > benzened. benzene > methyl m-nitrobenzoate > methyl benzoatee. methyl m-nitrobenzoate > benzene > methyl benzoate

_____ 27. A At what reaction conditions would the cyanuric chloride yield the product shown below?

a. 70E C, excess ethylamineb. 25E C, excess cyanuric chloridec. 0E C, excess ethylamined. 90E C, excess cyanuric chloridee. 25E C, excess ethylamine

_____ 28. B A student spills concentrated sulfuric acid on their hand, what should the student do?a. go find the TA and let them know what happenedb. go to the sink and begin running water over the affected areac. drive themselves to the hospital for the appropriate treatmentd. do nothing, sulfuric acid is not harmfule. pour a solution of sodium hydroxide on the hand to neutralize the acid



_____ 29. B Which test result is considered positive when it produces a wine-purple solution?a. the Tollens’ testb. the Schiff’s reagentc. the 2,4-DNP testd. the iodoform teste. the preparation of a semicarbazone

_____ 30. B In the Aldol Condensation lab you performed a computer analysis on the TPCP molecule.One of the questions asked why the molecule is not completely planar. What prevents thismolecule from being planar?a. it is not aromaticb. steric interactions between the phenyl groupsc. conjugation is maximized with phenyl groups perpendicular to 5-membered ring.d. attraction between π systems of aromatic ringse. 5-membered ring is puckered.

_____ 31. C Which structure below might reasonably have a fruity odor?

a.

CO2H

CH3O

b. CH3CH2CH2OCH2CH2CH3

c. CH3 CHCH2CH2OCCH3

O

CH3

d.

CH2OH

e. HCO2H

_____ 32. C Why was a sonicator used to start the Grignard reaction?a. To give kinetic energy to the moleculesb. To force the molecules to come togetherc. To shake off the oxide from the magnesium turningsd. To remove oxygen from the solutione. To heat up the solution

_____ 33. D Which of the following statements is/are false?1. The Eschweiler-Clarke reaction can be used to prepare tertiary amines from primary

and secondary amines.

2. Tertiary amines can be produced in good yield by alkylating a primary amine with analkyl halide.

3. An imine is formed as an intermediate in the Eschweiler-Clarke reaction.

4. Alkylation of secondary amines using excess alkyl halide results in the formation of aquaternary ammonium salt.

a. 1 and 3b. 2 and 4

c. 4 onlyd. 2 only

e. none of these



_____ 34. D You start the nitration reaction with 6.8 g of methyl benzoate and an excess of other neededreagents. If you obtain 7.2 g of the expected nitration product, your yield isa. 85 %b. 90 %

c. 75 %d. 80 %

e. 70 %

_____ 35. D In comparison to LiAlH4, sodium borohydride is a ______ reducing agent that is capable ofreducing ______.a. milder; amides and carboxylic acidsb. more powerful; aldehydes, carboxylic acids, esters and amidesc. more powerful; esters, ketones and amidesd. milder, aldehydes and ketonese. a and d

_____ 36. E TLC is a technique easily used fora. the qualitative monitoring of reactionsb. the quantitative monitoring of reactionsc. purification of large amounts of an impure compoundd. evaluation of the purity of a starting materiale. a and d

_____ 37. E Which statement is NOT correct about THF?a. It’s flammableb. Always handle it under the hoodc. Don’t contact your skind. It’s a good solvente. It’s not soluble in water

_____ 38. E Triazine herbicides work by mimicking _______, which is a small molecule involved inphotosynthesis.a. oxidosqualeneb. simazinec. chlorophylld. benzoquinonee. plastoquinone

_____ 39. A In the aldol condensation of dibenzyl ketone and benzil to form TPCP, __________ firstloses hydrogen to form the enolate.a. dibenzyl ketoneb. TPCPc. benzild. KOHe. ethanol

_____ 40. A The absorbance of a compound with a concentration 7.5 mM at 330 nm is 1.5. If the pathlength was 1 cm, what is the extinction coefficient of the compound at 330 nm?a. 200 M-1 cm-1 b. 20,000 M-1 cm-1

c. 20 M-1 cm-1 d. 2000 M-1 cm-1 e. 2 M-1 cm-1



_____ 41. B Aspartame, a non-nutritive sweetener, can be written as:a. H-Asp-Glu-OCH3

b. H-Asp-Phe-OCH3

c. H-Val-Asp-OCH2CH3

d. H-Arg-Phe-OCH3

e. H-Thr-His-OCH3

_____ 42. C An unknown compound gives a heavy, yellow-orange precipitate on mixing with 2,4-DNP. Treatment with the iodoform reagents yields a yellowish precipitate with a strong, medicinalodor. No particular change in appearance is observed in running the Tollens' test. If theunknown is one of the following compounds, it is most probably:

a. CH3CH2CH2OH1

b.

O1

CH3CH2CH2CH2

c.

O1

C2

CH3 3

CH2CH(CH3)24

d.

O1

C2

CH3 3

H 4

e.

O1

C2

CH3CH23

4

5 6

7

89

_____ 43. C The hydrolysis of esters can be done by both acid or base catalysis, however esterification ofcarboxylic acids can only be done by acid catalysis. Why is this?a. We cannot make a strong enough base to perform the reaction.b. Base will ruin the product produced.c. The carboxylic acid will be deprotonated by the base and will leave an unreactive

carboxylate anion.d. The reaction can be catalyzed by base.e. none of these

_____ 44. D In the addition of the HBr to butadiene, which product is the product of thermodynamiccontrol?a. 1,4-dibromo-2-butaneb. 3-bromo-1-butenec. 1-bromo-3-butene

d. 1-bromo-2-butenee. 1,2-dibromo-3-butene

_____ 45. D In the esterification of benzoic acid with methanol, which of the following statements is true?

1. The excess methanol increases the yield of the ester.

2. The H2SO4 catalyzes the reaction.

3. Adding H2O will increase the yield of the ester.

a. 1 onlyb. 1 and 3

c. 2 and 3d. 1 and 2

e. 1, 2 and 3



_____ 46. E In the Borohydride reduction of a ketone experiment, two product alcohols were obtained indifferent ratios. Select the correct option for A, B, and C in the scheme below.

a. A: Borneol B: Camphor/endo C: Isoborneol/exob. A: Camphor B: Borneol/exo C: Isoborneol/endoc. A: Isoborneol B: Isoborneol/exo C: Camphor/endod. A: Camphor B: Isoborneol/endo C: Borneol/exoe. A: Camphor B: Borneol/endo C: Isoborneol/exo

_____ 47. E Which of the following statements is false about Grignard Reaction?a. The Grignard reagent may be viewed as a strong base.b. Grignard reagents are prepared by the reaction of alkyl or aryl halides with magnesium.c. Grignard reagents are most often used in reactions with aldehydes or ketones.d. Grignard reagents react with acids to give alkanes.e. Alcohols are often used as solvents in the Grignard Reactions.

_____ 48. E Avobenzone and oxybenzone are sunscreen ingredients that both protect against ____ rays.a. UVBb. UVA

c. UVCd. UVA and UVC

e. UVA and UVB

_____ 49. A The electrophile for nitration of an aromatic compound is:a. NO2

+

b. NO3–

c. NOd. NO2

–e. NO+

_____ 50. A In the preparation of simazine experiment you used or produced several compounds. Whichof the following statements about them is false?a. Simazine is more soluble in water than ethylamine.b. Cyanuric chloride is already dissolved in acetone prior to use in the experiment.c. Cyanuric chloride is a solid.d. Simazine is non-toxic to humans.e. Ethylamine and cyanuric chloride are irritants.

CH3H3C

H3C O

CH3H3C

H3C

CH3H3C

H3C

OH

H

OH

H

A

B

C

NaBH4

EtOH, Heat

238 finial exam

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