Organic Chemistry Exam 4 MC LATEST QUE gf gf gf gf gf gf
STIONS AND 100- Verified ANSWERS. gf gf gf gf
Organic Chemistry Exam 4 – Multiple Choice
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1. Which of the following carbonyl compounds is most reactive toward nucleophilic acyl s
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ubstitution?
A) Amide
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B) Ester
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C) Acid chloride
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D) Carboxylate ion
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Correct Answer: C (Acid chloride – the chloride is a good leaving group.)
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2. What is the major product of the aldol addition reaction of acetaldehyde (ethanal) unde
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r basic conditions?
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A) 2-Butenal
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B) 3-Hydroxybutanal
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C) Butanoic acid
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D) 2-Butanone
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Correct Answer: B (3-Hydroxybutanal is the β-
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hydroxy aldehyde from aldol addition; dehydration gives 2-butenal.)
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3. Which reagent would you use to reduce a nitrile to a primary amine?
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A) NaBH₄
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B) LiAlH₄
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C) H₂ with Pd/C
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D) CrO₃
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Correct Answer: B (LiAlH₄ reduces nitriles to primary amines; NaBH₄ is too weak.)
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4. In the Claisen condensation of ethyl acetate, what is the final product after acidic worku
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p?
A) Ethyl acetoacetate
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B) Acetoacetic acid
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,C) Ethyl 3-oxobutanoate
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D) Both B and C
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Correct Answer: D (Ethyl 3-oxobutanoate is the β-
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keto ester; after acidic workup, it may hydrolyze/decarboxylate to acetoacetic acid if heated.)
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5. Which of the following best describes an enamine?
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A) An alkene with an amine group on the same carbon
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B) An amine with a C=C–N structure
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C) A product of ketone + secondary amine with acid catalysis
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D) Both B and C
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Correct Answer: D (Enamines have C=C–
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N, formed from ketones/aldehydes + secondary amine.)
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6. The Gabriel synthesis is used to prepare:
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A) Primary amines
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B) Secondary amines
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C) Tertiary amines
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D) Quaternary ammonium salts
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Correct Answer: A (Phthalimide + alkyl halide + hydrolysis yields primary amines.)
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7. Which carbohydrate is a non-reducing sugar?
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A) Glucose
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B) Fructose
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C) Sucrose
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D) Lactose
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Correct Answer: C (Sucrose has an acetal linkage between anomeric carbons of glucose and fruc
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tose, so no free hemiacetal.)
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8. In the Wittig reaction, a phosphonium ylide reacts with a ketone to form:
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A) An epoxide
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B) An alkene
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C) An alcohol
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D) An alkyne
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Correct Answer: B (Ylide + carbonyl → alkene + triphenylphosphine oxide.)
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,9. What is the product of the reduction of a carboxylic acid with LiAlH₄?
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A) Aldehyde
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B) Ketone
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C) Primary alcohol
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D) Alkane
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Correct Answer: C (LiAlH₄ reduces –COOH to –CH₂OH.)
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10. The Michael reaction involves:
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A) Addition of an enolate to an α,β-unsaturated carbonyl
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B) Reaction of an aldehyde with an amine
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C) Electrophilic aromatic substitution
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D) Reduction of a nitro group
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Correct Answer: A (Michael addition = conjugate addition of a nucleophile to an α,β-
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unsaturated carbonyl.) gf
11. Which compound would give a positive iodoform test (yellow precipitate with I₂/NaO
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H)?
A) 3-Pentanone
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B) Ethanol
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C) Benzophenone
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D) Acetic acid
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Correct Answer: B (Ethanol is oxidized to acetaldehyde in the test; compounds with CH₃C=O or
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CH₃CHOH give positive.) gf gf
12. In the Hell-Volhard-
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Zelinsky (HVZ) reaction, what is the product when propanoic acid is treated with Br₂ + PBr
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₃?
A) 2-Bromopropanoic acid
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B) 3-Bromopropanoic acid
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C) Propionyl bromide
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D) 2,2-Dibromopropanoic acid
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Correct Answer: A (α-Bromination of carboxylic acid.)
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, 13. Which of the following is a reducing sugar?
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A) Sucrose
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B) Starch
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C) Maltose
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D) Cellulose
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Correct Answer: C (Maltose has a free anomeric carbon.)
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14. The Hofmann elimination of a quaternary ammonium hydroxide favors formation of:
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A) The most substituted alkene
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B) The least substituted alkene
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C) A mixture of alkenes
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D) An alkyne
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Correct Answer: B (Hofmann rule: least substituted alkene (anti-Zaitsev) due to bulky base.)
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15. What is the main product of a crossed aldol reaction between benzaldehyde and aceto
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phenone with NaOH? gf gf
A) 1,3-Diphenyl-2-propen-1-one (chalcone)
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B) 1,3-Diphenylpropan-1-one
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C) 2-Hydroxy-1,3-diphenylpropan-1-one
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D) Benzyl alcohol
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Correct Answer: A (Aldol addition then dehydration gives α,β-unsaturated ketone = chalcone.)
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16. Which amino acid has an aromatic side chain?
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A) Glycine
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B) Valine
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C) Tryptophan
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D) Serine
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Correct Answer: C (Tryptophan has an indole ring; phenylalanine and tyrosine also aromatic.)
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17. The Robinson annulation combines which two reactions?
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A) Wittig + Diels-Alder
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B) Michael addition + aldol condensation
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C) Claisen + Dieckmann
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D) Grignard + halogenation
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STIONS AND 100- Verified ANSWERS. gf gf gf gf
Organic Chemistry Exam 4 – Multiple Choice
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1. Which of the following carbonyl compounds is most reactive toward nucleophilic acyl s
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ubstitution?
A) Amide
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B) Ester
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C) Acid chloride
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D) Carboxylate ion
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Correct Answer: C (Acid chloride – the chloride is a good leaving group.)
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2. What is the major product of the aldol addition reaction of acetaldehyde (ethanal) unde
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r basic conditions?
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A) 2-Butenal
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B) 3-Hydroxybutanal
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C) Butanoic acid
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D) 2-Butanone
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Correct Answer: B (3-Hydroxybutanal is the β-
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hydroxy aldehyde from aldol addition; dehydration gives 2-butenal.)
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3. Which reagent would you use to reduce a nitrile to a primary amine?
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A) NaBH₄
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B) LiAlH₄
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C) H₂ with Pd/C
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D) CrO₃
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Correct Answer: B (LiAlH₄ reduces nitriles to primary amines; NaBH₄ is too weak.)
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4. In the Claisen condensation of ethyl acetate, what is the final product after acidic worku
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p?
A) Ethyl acetoacetate
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B) Acetoacetic acid
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,C) Ethyl 3-oxobutanoate
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D) Both B and C
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Correct Answer: D (Ethyl 3-oxobutanoate is the β-
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keto ester; after acidic workup, it may hydrolyze/decarboxylate to acetoacetic acid if heated.)
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5. Which of the following best describes an enamine?
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A) An alkene with an amine group on the same carbon
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B) An amine with a C=C–N structure
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C) A product of ketone + secondary amine with acid catalysis
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D) Both B and C
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Correct Answer: D (Enamines have C=C–
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N, formed from ketones/aldehydes + secondary amine.)
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6. The Gabriel synthesis is used to prepare:
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A) Primary amines
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B) Secondary amines
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C) Tertiary amines
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D) Quaternary ammonium salts
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Correct Answer: A (Phthalimide + alkyl halide + hydrolysis yields primary amines.)
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7. Which carbohydrate is a non-reducing sugar?
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A) Glucose
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B) Fructose
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C) Sucrose
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D) Lactose
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Correct Answer: C (Sucrose has an acetal linkage between anomeric carbons of glucose and fruc
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tose, so no free hemiacetal.)
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8. In the Wittig reaction, a phosphonium ylide reacts with a ketone to form:
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A) An epoxide
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B) An alkene
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C) An alcohol
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D) An alkyne
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Correct Answer: B (Ylide + carbonyl → alkene + triphenylphosphine oxide.)
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,9. What is the product of the reduction of a carboxylic acid with LiAlH₄?
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A) Aldehyde
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B) Ketone
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C) Primary alcohol
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D) Alkane
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Correct Answer: C (LiAlH₄ reduces –COOH to –CH₂OH.)
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10. The Michael reaction involves:
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A) Addition of an enolate to an α,β-unsaturated carbonyl
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B) Reaction of an aldehyde with an amine
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C) Electrophilic aromatic substitution
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D) Reduction of a nitro group
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Correct Answer: A (Michael addition = conjugate addition of a nucleophile to an α,β-
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unsaturated carbonyl.) gf
11. Which compound would give a positive iodoform test (yellow precipitate with I₂/NaO
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H)?
A) 3-Pentanone
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B) Ethanol
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C) Benzophenone
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D) Acetic acid
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Correct Answer: B (Ethanol is oxidized to acetaldehyde in the test; compounds with CH₃C=O or
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CH₃CHOH give positive.) gf gf
12. In the Hell-Volhard-
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Zelinsky (HVZ) reaction, what is the product when propanoic acid is treated with Br₂ + PBr
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₃?
A) 2-Bromopropanoic acid
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B) 3-Bromopropanoic acid
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C) Propionyl bromide
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D) 2,2-Dibromopropanoic acid
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Correct Answer: A (α-Bromination of carboxylic acid.)
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, 13. Which of the following is a reducing sugar?
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A) Sucrose
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B) Starch
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C) Maltose
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D) Cellulose
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Correct Answer: C (Maltose has a free anomeric carbon.)
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14. The Hofmann elimination of a quaternary ammonium hydroxide favors formation of:
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A) The most substituted alkene
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B) The least substituted alkene
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C) A mixture of alkenes
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D) An alkyne
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Correct Answer: B (Hofmann rule: least substituted alkene (anti-Zaitsev) due to bulky base.)
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15. What is the main product of a crossed aldol reaction between benzaldehyde and aceto
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phenone with NaOH? gf gf
A) 1,3-Diphenyl-2-propen-1-one (chalcone)
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B) 1,3-Diphenylpropan-1-one
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C) 2-Hydroxy-1,3-diphenylpropan-1-one
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D) Benzyl alcohol
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Correct Answer: A (Aldol addition then dehydration gives α,β-unsaturated ketone = chalcone.)
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16. Which amino acid has an aromatic side chain?
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A) Glycine
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B) Valine
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C) Tryptophan
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D) Serine
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Correct Answer: C (Tryptophan has an indole ring; phenylalanine and tyrosine also aromatic.)
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17. The Robinson annulation combines which two reactions?
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A) Wittig + Diels-Alder
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B) Michael addition + aldol condensation
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C) Claisen + Dieckmann
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D) Grignard + halogenation
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