CHM 2210 Final Exam V2 | CHM 2210
Organic Chemistry I | Actual Q&A with
Rationale (CHM2210 Final Exam) |
University of Central Florida
1. Which hybridization is associated with a carbon atom in a triple bond?
A. sp3
B. sp2
C. sp3d
D. sp
Answer: D
Rationale: Carbon atoms involved in triple bonds utilize sp hybridization to accommodate
two sigma bonds and two pi bonds. This electronic configuration results in a linear
molecular geometry with bond angles of 180 degrees. The orbital overlap is most efficient
when the p-orbitals are oriented perpendicular to each other.
2. Which of the following describes the relationship between (R)-2-chlorobutane and (S)-2-
chlorobutane?
A. Diastereomers
B. Constitutional isomers
C. Enantiomers
,D. Identical
Answer: C
Rationale: These two molecules are non-superimposable mirror images of each other,
which defines them as enantiomers. They possess the same physical properties except for
the direction in which they rotate plane-polarized light. In a laboratory setting, separating
such isomers usually requires a chiral environment or resolving agent.
3. Which reagent is best suited for the anti-Markovnikov addition of water to an alkene?
A. H2O, H2SO4
B. Hg(OAc)2, H2O followed by NaBH4
C. BH3-THF followed by H2O2, NaOH
D. KMnO4, NaOH
Answer: C
Rationale: Hydroboration-oxidation is the standard method for achieving anti-
Markovnikov hydration of an alkene. The boron atom adds to the less substituted carbon
due to steric and electronic factors during the transition state. Subsequent oxidation
replaces the boron with a hydroxyl group, maintaining the syn-stereochemistry.
4. In an SN2 reaction, which type of alkyl halide reacts the fastest?
A. Primary
B. Methyl
, C. Secondary
D. Tertiary
Answer: B
Rationale: The SN2 mechanism involves a backside attack by a nucleophile, which is highly
sensitive to steric hindrance. Methyl halides offer the least resistance to the incoming
nucleophile because they lack bulky alkyl groups. Tertiary substrates are essentially
unreactive in SN2 conditions due to the congestion around the electrophilic carbon.
5. What is the correct formal charge on the nitrogen atom in the ammonium ion (NH4+)?
A. -1
B. 0
C. +2
D. +1
Answer: D
Rationale: Nitrogen normally has five valence electrons in its neutral state. In the
ammonium ion, it shares four pairs of electrons, giving it an assigned count of four
electrons for formal charge calculation. Subtracting four from five results in a formal
charge of +1 on the central nitrogen atom.
6. Which conformer of cyclohexane is the least stable?
A. Chair
Organic Chemistry I | Actual Q&A with
Rationale (CHM2210 Final Exam) |
University of Central Florida
1. Which hybridization is associated with a carbon atom in a triple bond?
A. sp3
B. sp2
C. sp3d
D. sp
Answer: D
Rationale: Carbon atoms involved in triple bonds utilize sp hybridization to accommodate
two sigma bonds and two pi bonds. This electronic configuration results in a linear
molecular geometry with bond angles of 180 degrees. The orbital overlap is most efficient
when the p-orbitals are oriented perpendicular to each other.
2. Which of the following describes the relationship between (R)-2-chlorobutane and (S)-2-
chlorobutane?
A. Diastereomers
B. Constitutional isomers
C. Enantiomers
,D. Identical
Answer: C
Rationale: These two molecules are non-superimposable mirror images of each other,
which defines them as enantiomers. They possess the same physical properties except for
the direction in which they rotate plane-polarized light. In a laboratory setting, separating
such isomers usually requires a chiral environment or resolving agent.
3. Which reagent is best suited for the anti-Markovnikov addition of water to an alkene?
A. H2O, H2SO4
B. Hg(OAc)2, H2O followed by NaBH4
C. BH3-THF followed by H2O2, NaOH
D. KMnO4, NaOH
Answer: C
Rationale: Hydroboration-oxidation is the standard method for achieving anti-
Markovnikov hydration of an alkene. The boron atom adds to the less substituted carbon
due to steric and electronic factors during the transition state. Subsequent oxidation
replaces the boron with a hydroxyl group, maintaining the syn-stereochemistry.
4. In an SN2 reaction, which type of alkyl halide reacts the fastest?
A. Primary
B. Methyl
, C. Secondary
D. Tertiary
Answer: B
Rationale: The SN2 mechanism involves a backside attack by a nucleophile, which is highly
sensitive to steric hindrance. Methyl halides offer the least resistance to the incoming
nucleophile because they lack bulky alkyl groups. Tertiary substrates are essentially
unreactive in SN2 conditions due to the congestion around the electrophilic carbon.
5. What is the correct formal charge on the nitrogen atom in the ammonium ion (NH4+)?
A. -1
B. 0
C. +2
D. +1
Answer: D
Rationale: Nitrogen normally has five valence electrons in its neutral state. In the
ammonium ion, it shares four pairs of electrons, giving it an assigned count of four
electrons for formal charge calculation. Subtracting four from five results in a formal
charge of +1 on the central nitrogen atom.
6. Which conformer of cyclohexane is the least stable?
A. Chair
