Q: Which of the following is typically NOT a characteristic of a good leaving group? A) It is a weak base. B) It can stabilize a negative charge. C) It is a strong nucleophile. D) It can depart as a stable anion. A: C) It is a strong nucleophile.
Q: What is the primary product when an aldehyde reacts with an excess of a Grignard reagent, followed by acidic workup? A) A primary alcohol B) A secondary alcohol C) A tertiary alcohol D) A ketone A: B) A secondary alcohol
Q: The reaction of an alkyl halide with a strong nucleophile in a polar aprotic solvent favors which mechanism? A) S$_N1B)S_N2C)E1D)E2∗∗A:∗∗B)S_N$2
Q: Which of the following compounds is most likely to undergo an S$_N1reaction?A)CH_3BrB)CH_3CH_2BrC)(CH_3$)2CHBr D) (CH$_3$)3CBr A: D) (CH$_3$)3CBr
Q: What is the term for the process where a carbonyl compound and its enol form are in equilibrium? A) Isomerization B) Racemization C) Tautomerism D) Conjugation A: C) Tautomerism
Q: Which electrophile is generated for the Friedel-Crafts acylation reaction? A) Carbocation (R$^+)B)Nitroniumion(NO_2^+)C)Acyliumion(RCO^+)D)Sulfurtrioxide(SO_3$) A: C) Acylium ion (RCO$^+$)
Q: What type of addition is characteristic of the reaction of Br$_2$ with an alkene? A) Syn-addition B) Anti-addition C) Markovnikov addition D) Hofmann addition A: B) Anti-addition
Q: Which of the following is generally considered a “hard” nucleophile, favoring 1,2-addition to α,β-unsaturated carbonyls? A) Gilman reagent (R$_2$CuLi) B) Amine C) Grignard reagent (RMgX) D) Enolate A: C) Grignard reagent (RMgX)
Q: What is the primary product of the ozonolysis of 2-butene followed by reductive workup? A) Propanal B) Acetone C) Acetaldehyde D) Ethane A: C) Acetaldehyde
Q: Which of the following substituents is an ortho, para-directing deactivator in Electrophilic Aromatic Substitution? A) -OH B) -NO$_2$ C) -Cl D) -CH$_3$ A: C) -Cl
Q: How does increasing temperature generally influence the competition between substitution and elimination reactions? A) Favors substitution B) Favors elimination C) Has no effect D) Depends on the solvent type only A: B) Favors elimination
Q: In an E2 reaction, the base abstracts a proton that is ________ to the leaving group. A) Syn-periplanar B) Gauche C) Anti-periplanar D) Cis A: C) Anti-periplanar
Q: Which of the following carboxylic acid derivatives is the MOST reactive towards nucleophilic substitution at the carbonyl group? A) Amide B) Ester C) Acid Anhydride D) Acyl Chloride A: D) Acyl Chloride
Q: The main reason that Friedel-Crafts alkylation can lead to polyalkylation is that: A) The carbocation intermediate is very stable. B) The alkylated product is more reactive towards EAS than the starting material. C) The reaction is reversible. D) The AlCl$_3$ catalyst is very strong. A: B) The alkylated product is more reactive towards EAS than the starting material.
Q: What is the major functional group formed when an aldehyde undergoes nucleophilic addition with HCN? A) Hemiacetal B) Cyanohydrin C) Acetone D) Carboxylic acid A: B) Cyanohydrin
Q: Which type of catalysis is required for acetal formation from an aldehyde/ketone and an alcohol? A) Base catalysis B) Acid catalysis C) Radical initiation D) Metal catalysis A: B) Acid catalysis
Q: A molecule that is electron-deficient and has an empty orbital to accept electrons is called a(n): A) Nucleophile B) Electrophile C) Radical D) Leaving group A: B) Electrophile
Q: What is the stereochemical outcome of an S$_N$1 reaction at a chiral center? A) Complete inversion of configuration B) Complete retention of configuration C) Racemization D) Formation of a single diastereomer A: C) Racemization
Q: In the nitration of benzene, what is the active electrophile? A) H$_3O^+$ B) NO$_2^+$ C) SO$_3$ D) NO$_3$⁻ A: B) NO$_2^+$
Q: What phenomenon explains why the keto form of a carbonyl compound is usually more stable than its enol form? A) Hyperconjugation B) Resonance C) Steric hindrance D) Tautomerism (Keto-enol equilibrium favors keto due to stronger C=O bond) A: D) Tautomerism (Keto-enol equilibrium favors keto due to stronger C=O bond)
Q: Which of the following statements about curly arrows is FALSE? A) They show the movement of a pair of electrons. B) They start from an electron-rich site. C) They can start from a positive charge. D) They end where a new bond is forming or a negative charge is accumulating. A: C) They can start from a positive charge.
Q: The reaction of an aldehyde or ketone with a primary amine to form an imine involves the loss of what small molecule? A) HCN B) H$_2OC)CO_2$ D) NH$_3$ A: B) H$_2$O
Q: Markovnikov’s rule is applied to predict the regioselectivity of which reaction type? A) S$_N$2 reactions B) E2 eliminations C) Electrophilic addition of HX to alkenes D) Friedel-Crafts reactions A: C) Electrophilic addition of HX to alkenes
Q: Which reaction mechanism involves the formation of a Meisenheimer complex? A) S$_N1B)S_NAr(NucleophilicAromaticSubstitution)C)EAS(ElectrophilicAromaticSubstitution)D)Wittigreaction∗∗A:∗∗B)S_N$Ar (Nucleophilic Aromatic Substitution)
Q: The use of Weinreb amides is a common solution to what problem in organic synthesis? A) Carbocation rearrangements in alkylation. B) Over-addition of Grignard reagents to esters when synthesizing ketones. C) The slow rate of S$_N$2 reactions on tertiary substrates. D) The lack of regioselectivity in E1 eliminations. A: B) Over-addition of Grignard reagents to esters when synthesizing ketones.