Organic Chemistry 1 ACS Questions 2024 Final Exam multiple choice with Answers, Exams of Chemistry

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Organic Chemistry 1 ACS Questions 2024 Final Exam

multiple choice with Answers

Which is the correct hybridization state and geometry for the carbon atom in HCN? sp, linear sp2, trigonal planar sp3, tetrahedral None of the above - Answer- sp, linear The following structure has been drawn without formal charges. Which statement describes the missing formal charge(s)? This structure has one positive charge and one negative charge. This structure has one positive charge but no negative charges. This structure has one negative charge but no positive charges. This structure has no formal charges. - Answer- This structure has one positive charge and one negative charge. The indicated σ bond results from the overlap of which orbitals? sp2-sp sp-sp sp-sp sp2-sp3 - Answer- sp2-sp

Of the following molecular geometries, which has the largest bond angle? Pyramidal Tetrahedral Trigonal planar Bent - Answer- Trigonal planar How many σ bonds are in the following compound? 8 9 13 14 - Answer- 13

Which compound has the higher boiling point? Explain briefly. X, because the dipole moments are far apart. Y, because the dipole moments do not fully cancel. Y, because it is less branched. X, because it is more linear. - Answer- Y, because the dipole moments do not fully cancel. How many hydrogen atoms are in the compound represented by the following bond-line drawing? 5 6 7 8 - Answer- 6 The compound represented by the following bond-line drawing has how many carbon atoms and how many π bonds? C atoms π bonds (a)

(b) 10 5 (c) 9 6 (d) 9 5 - Answer- D) 9 5 All of the following are significant resonance structures of the benzyl carbocation, EXCEPT: - Answer- C

Which of the following resonance structures is the most significant contributor to the resonance hybrid? - Answer- A Which of the following structures exhibits an sp3-hybridized nitrogen atom? - Answer- D Which is a bond-line drawing of (CH3)2CHCH2OC(CH3)3? - Answer- C Which of the following has the correct curved arrow(s) placement to show resonance for the given allylic carbocation? - Answer- C

Which of the following anions is resonance delocalized? - Answer- A The following cation has a total of how many resonance structures? - Answer- A Which of the following best represents the resonance hybrid of the given anion? - Answer- D

Which of the following does NOT represent a pair of resonance structures? - Answer- B What is the strongest base that is present after methyl magnesium bromide (CH3MgBr) is treated with water? - Answer- C Which side of the following equilibrium is favored? The right side. The left side. Depends on temperature. Cannot determine without more information. - Answer- The right side

All of the following are more acidic than water (H2O) EXCEPT: - Answer- C All of the following are Lewis bases EXCEPT: - Answer- D Arrange the following compounds in order of increasing acidity, from the weakest acid to the strongest acid. II < I < III II < III < I

I < III < II

III < II < I - Answer- II < III < I Which is the stronger acid, HCl or HBr? Explain briefly. HCl is the stronger acid because Cl is more electronegative than Br. HCl is the stronger acid because Cl is smaller than Br. HBr is the stronger acid because Br is less electronegative than Cl. HBr is the stronger acid because Br is larger than Cl. - Answer- HBr is the stronger acid because Br is larger than Cl. Which of the indicated protons in the given compound is the most acidic? Proton A Proton B Proton C Proton D - Answer- Proton D

Which of the given compounds is more acidic? Briefly explain. X is the stronger acid because the acidic proton is on a more electronegative atom. X is the stronger acid because its conjugate base is stabilized by inductive effects. Y is the stronger acid because its conjugate base is stabilized by resonance. Y is the stronger acid because the acidic proton is stabilized by inductive effects. - Answer- Y is the stronger acid because its conjugate base is stabilized by resonance. Of the following, which is the strongest base? - Answer- A All of the following are representations of cis-1,2-dimethylcyclohexane, EXCEPT: - Answer- D

All of the following are representations of 2-methylpentane, EXCEPT: - Answer- B Which of the following is expected to have the largest heat of combustion? - Answer- C Which of the following is a constitutional isomer of heptane? - Answer- D Provide a systematic name for the following compound. 4 - isopropylpentane 2 - isopropylpentane 5,6-dimethylhexane 2,3-dimethylhexane - Answer- 2,3-dimethylhexane

Which of the following represents the most stable conformation of cis-1,4-dimethylcyclohexane? - Answer- C Which of the following conformers has one or more gauche interactions? - Answer- B Which of the following represents the most stable conformation of the given compound? - Answer- C

Which of the following is the correct IUPAC name for the tertbutyl substituent? (1,1-dimethylethyl) (1,1,1-trimethyl) (1-methyl- 2 - propyl) 2 - methyl- 2 - propyl) - Answer- (1,1-dimethylethyl) What is the configuration of the chiral center in the following compound? R S Z Depends on T - Answer- R What is the relationship between the following two compounds? Enantiomers Diastereomers Constitutional isomers

Resonance forms - Answer- Diastereomers Which of these compounds is expected to be optically active at room temperature? - Answer- D Identify the meso compound(s). I only II only I and III only I, II, and III - Answer- II only Is the following compound chiral, and does it have an enantiomer?

It is not chiral, and it does not have an enantiomer. It is not chiral, but it does have an enantiomer. It is chiral, and it has an enantiomer. It is chiral, but it does not have an enantiomer. - Answer- It is not chiral, and it does not have an enantiomer. Arrange the given substituents in order of increasing priority (based on Cahn-Ingold-Prelog rules), from lowest to highest priority. III < II < I III < I < II II < I < III I < II < III - Answer- II < I < III For a reaction with ΔG < 0, which of the following MUST be true? The reaction must be exothermic The reaction must be endothermic Keq > 1 None of the above - Answer- Keq > 1

Which of the following can serve as a nucleophile? - Answer- D In the following energy diagram showing the progress of a reaction, which location(s) represent an intermediate? I, III, and V II and IV Only III I, II, III, IV, and V - Answer- II and IV Which best describes the change in entropy for the following reaction? ΔS > 0 ΔS = 0 ΔS < 0 ΔS = 1 - Answer- ΔS < 0

Which best represents the transition state of the following reaction? - Answer- A For a reaction with ΔH < 0, which of the following must be true? All bonds are broken homolytically. All bonds are broken heterolytically. The bonds broken are stronger than the bonds formed. The bonds broken are weaker than the bonds formed. - Answer- The bonds broken are weaker than the bonds formed. The rate expression for a reaction was found to be: Rate=k[Et Br][Na Sh] This reaction is best described as zero order bimolecular unimolecular rate-determining - Answer- bimolecular

What type of reaction steps are represented below? loss of a leaving group, followed by loss of a leaving group proton transfer, followed by loss of a leaving group nucleophilic attack, followed by proton transfer proton transfer, followed by nucleophilic attack - Answer- proton transfer, followed by loss of a leaving group For the following substitution reaction, which statement is FALSE? The process is bimolecular. Increasing the concentration of hydroxide will cause an increase in the rate of reaction. The use of a polar aprotic solvent will enhance the rate. The reaction proceeds via a carbocation intermediate. - Answer- The reaction proceeds via a carbocation intermediate. Which is the major product of this reaction? - Answer- D

Of the following, which is the most efficient synthesis of 1-butene (CH3CH2CH═CH2)? - Answer- C Which of the following is NOT favorable for an SN2 reaction? A leaving group on a primary carbon atom A polar aprotic solvent A strong nucleophile Increased steric hindrance - Answer- Increased steric hindrance Which mechanism involves a carbocation electrophile reacting with a weak nucleophile? SN SN E E2 - Answer- SN Which of the following best represents the transition state of the rate-determining step for the given reaction? - Answer- B

Sodium ethoxide (NaOEt) is a suitable reagent to promote which mechanism(s)? SN SN E E a.I and II b.I and III c. II and IV d. III and IV - Answer- c. II and IV Which is the best reagent to achieve the following transformation? t-BuOK NaOH CH3OH Conc. H2SO4 - Answer- t-BuOK

Which substrate undergoes the fastest solvolysis reaction with methanol (CH3OH)? - Answer- D Which is the faster reaction and why? I is faster because it has a better nucleophile. I is faster because it has less steric hindrance. II is faster because it has the better leaving group. II is faster because it has the more stable carbocation. - Answer- I is faster because it has less steric hindrance. Which disconnection leads to the most reasonable retrosynthesis of the given target molecule? - Answer- C

Which of the following is not a reasonable retrosynthesis? - Answer- A Which of the following compounds is NOT a product of this ozonolysis reaction? - Answer- C Which of the following represents an efficient method for preparing the alcohol shown? - Answer- D

Consider the following acid-catalyzed hydration reaction: Which of the following ions are intermediates in the accepted mechanism for this process? I, II, and III I and II None of the above. The process is concerted. Only IV - Answer- I and II Provide suitable reagents for the following transformation. - Answer- D Predict the major product of the following reaction. - Answer- B

Which of the following represents a likely step in the mechanism of the given reaction? - Answer- C Of the following, which is the most stable alkene? - Answer- D What is the IUPAC name of the given compound? (E)- 3 - butyl- 4 - methyl- 2 - pentene (Z)- 3 - butyl- 4 - methyl- 2 - pentene (E)- 3 - (1-methylethyl)- 2 - heptene (Z)- 3 - (2-propyl)- 2 - heptene - Answer- (E)- 3 - (1-methylethyl)- 2 - heptene

Which of the following compounds is converted into carbon dioxide and acetic acid (CH3CO2H) upon ozonolysis? - Answer- A All of the following methods can be used to prepare 2-butanone (CH3COCH2CH3) EXCEPT: - Answer- C Which reagents will achieve the following transformation? H2, Pt NaNH2/NH3