ACS Organic Chemistry I Certification
Examination Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
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Question 1
Carbon most commonly forms how many covalent bonds in organic compounds?
A. 2
B. 3
C. 4
D. 5
Answer: C. 4
Rationale: Carbon is tetravalent, meaning it typically forms four covalent bonds to
complete its octet.
Question 2
The hybridization of carbon in methane (CH₄) is:
A. sp
B. sp²
C. sp³d
,D. sp³
Answer: D. sp³
Rationale: In methane, carbon forms four single bonds, giving it four electron
domains and sp³ hybridization.
Question 3
An sp²-hybridized carbon has which molecular geometry?
A. Linear
B. Tetrahedral
C. Trigonal planar
D. Trigonal bipyramidal
Answer: C. Trigonal planar
Rationale: An sp² carbon has three regions of electron density arranged 120° apart
in a trigonal planar geometry.
Question 4
The bond angle in a tetrahedral carbon atom is approximately:
A. 90°
B. 109.5°
C. 120°
D. 180°
Answer: B. 109.5°
Rationale: A tetrahedral arrangement minimizes electron repulsion and has bond
angles of about 109.5°.
,Question 5
Which bond is the shortest?
A. Carbon–carbon single bond
B. Carbon–carbon double bond
C. Carbon–carbon triple bond
D. All are equal
Answer: C. Carbon–carbon triple bond
Rationale: Triple bonds have the greatest bond order and therefore are shorter
and stronger than double or single bonds.
Question 6
Which bond is generally the strongest?
A. C–C single bond
B. C=C double bond
C. C≡C triple bond
D. All have equal strength
Answer: C. C≡C triple bond
Rationale: Triple bonds have one sigma bond and two pi bonds, making them the
strongest carbon–carbon bonds.
Question 7
Which intermolecular force is present in all organic molecules?
A. Hydrogen bonding
B. Ion–dipole attraction
C. Dipole–dipole attraction
, D. London dispersion forces
Answer: D. London dispersion forces
Rationale: London dispersion forces arise from temporary dipoles and are present
in all molecules.
Question 8
A resonance structure differs from another resonance structure by the placement
of:
A. Atoms
B. Sigma bonds
C. Electrons
D. Functional groups
Answer: C. Electrons
Rationale: Resonance structures differ only in the positions of electrons, not the
arrangement of atoms.
Question 9
Resonance stabilization generally makes a molecule:
A. Less stable
B. More acidic only
C. More basic only
D. More stable
Answer: D. More stable
Rationale: Delocalization of electrons lowers the overall energy of the molecule,
increasing stability.
Examination Questions and Correct
Answers (Verified Answers) Plus
Rationales 2026 Q&A | Instant
Download Pdf
Question 1
Carbon most commonly forms how many covalent bonds in organic compounds?
A. 2
B. 3
C. 4
D. 5
Answer: C. 4
Rationale: Carbon is tetravalent, meaning it typically forms four covalent bonds to
complete its octet.
Question 2
The hybridization of carbon in methane (CH₄) is:
A. sp
B. sp²
C. sp³d
,D. sp³
Answer: D. sp³
Rationale: In methane, carbon forms four single bonds, giving it four electron
domains and sp³ hybridization.
Question 3
An sp²-hybridized carbon has which molecular geometry?
A. Linear
B. Tetrahedral
C. Trigonal planar
D. Trigonal bipyramidal
Answer: C. Trigonal planar
Rationale: An sp² carbon has three regions of electron density arranged 120° apart
in a trigonal planar geometry.
Question 4
The bond angle in a tetrahedral carbon atom is approximately:
A. 90°
B. 109.5°
C. 120°
D. 180°
Answer: B. 109.5°
Rationale: A tetrahedral arrangement minimizes electron repulsion and has bond
angles of about 109.5°.
,Question 5
Which bond is the shortest?
A. Carbon–carbon single bond
B. Carbon–carbon double bond
C. Carbon–carbon triple bond
D. All are equal
Answer: C. Carbon–carbon triple bond
Rationale: Triple bonds have the greatest bond order and therefore are shorter
and stronger than double or single bonds.
Question 6
Which bond is generally the strongest?
A. C–C single bond
B. C=C double bond
C. C≡C triple bond
D. All have equal strength
Answer: C. C≡C triple bond
Rationale: Triple bonds have one sigma bond and two pi bonds, making them the
strongest carbon–carbon bonds.
Question 7
Which intermolecular force is present in all organic molecules?
A. Hydrogen bonding
B. Ion–dipole attraction
C. Dipole–dipole attraction
, D. London dispersion forces
Answer: D. London dispersion forces
Rationale: London dispersion forces arise from temporary dipoles and are present
in all molecules.
Question 8
A resonance structure differs from another resonance structure by the placement
of:
A. Atoms
B. Sigma bonds
C. Electrons
D. Functional groups
Answer: C. Electrons
Rationale: Resonance structures differ only in the positions of electrons, not the
arrangement of atoms.
Question 9
Resonance stabilization generally makes a molecule:
A. Less stable
B. More acidic only
C. More basic only
D. More stable
Answer: D. More stable
Rationale: Delocalization of electrons lowers the overall energy of the molecule,
increasing stability.
