COMPREHENSIVE ORGANIC CHEMISTRY EXAMINATION: JANICE SMITH 6TH EDITION
COVERAGE
SECTION A: STRUCTURE, BONDING, AND ACIDS & BASES
1. What is the ground-state electronic configuration of a carbon atom?
A) 1s² 2s² 2p²
B) 1s² 2s² 2p³
C) 1s² 2s¹ 2p³
D) 1s² 2s² 2p⁴
Answer: A) 1s² 2s² 2p²
Rationale: Carbon has atomic number 6. The ground-state configuration follows the
Aufbau principle, with electrons filling the 1s, 2s, and then 2p orbitals sequentially. The
configuration 1s² 2s² 2p² correctly accounts for all six electrons.
2. What is the hybridization state of a carbon atom in a triple bond?
A) sp
B) sp²
C) sp³
D) sp³d
Answer: A) sp
Rationale: A carbon atom involved in a triple bond forms two σ bonds and two π bonds.
This requires two hybrid orbitals for σ bonding, resulting in sp hybridization with a linear
geometry (180° bond angles). The remaining two unhybridized p orbitals form the two π
bonds.
3. Which of the following correctly ranks the indicated bonds in order of increasing
bond strength?
A) C-C < C=C < C≡C
B) C≡C < C=C < C-C
C) C=C < C-C < C≡C
D) C-C < C≡C < C=C
Answer: A) C-C < C=C < C≡C
,Rationale: Bond strength increases with bond order. A single bond (C-C) has the lowest
bond dissociation energy, a double bond (C=C) is stronger, and a triple bond (C≡C) is the
strongest. However, note that the incremental increase is not proportional; the second and
third bonds in multiple bonds are weaker than the first.
4. Which element has the highest electronegativity on the Pauling scale?
A) Oxygen
B) Nitrogen
C) Chlorine
D) Fluorine
Answer: D) Fluorine
Rationale: Fluorine has the highest electronegativity value (4.0) on the Pauling scale. This
is due to its small atomic size and high effective nuclear charge, allowing it to strongly
attract electrons in a chemical bond. Oxygen (3.5), chlorine (3.0), and nitrogen (3.0) are
also highly electronegative but less than fluorine.
5. What is the correct ground-state electronic configuration of a chloride anion (Cl⁻)?
A) 1s² 2s² 2p⁶ 3s² 3p⁵
B) 1s² 2s² 2p⁶ 3s² 3p⁶
C) 1s² 2s² 2p⁶ 3s² 3p⁴
D) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Answer: B) 1s² 2s² 2p⁶ 3s² 3p⁶
Rationale: A chlorine atom (atomic number 17) has the configuration 1s² 2s² 2p⁶ 3s² 3p⁵.
When chlorine gains one electron to become Cl⁻, it achieves a full octet with the
configuration 1s² 2s² 2p⁶ 3s² 3p⁶, which is isoelectronic with argon.
6. What is the bond angle in a molecule with sp² hybridized carbon?
A) 90°
B) 109.5°
C) 120°
D) 180°
Answer: C) 120°
Rationale: sp² hybridization involves three equivalent hybrid orbitals arranged in a trigonal
planar geometry with bond angles of approximately 120°. This hybridization occurs in
molecules with three electron groups around the central atom, such as alkenes and
carbonyl compounds.
,7. How many π bonds are present in a molecule of benzene (C₆H₆)?
A) 1
B) 2
C) 3
D) 4
Answer: C) 3
Rationale: Benzene has a cyclic structure with alternating single and double bonds. It
contains three π bonds, one for each double bond. However, due to resonance, the π
electrons are delocalized across all six carbon atoms, giving benzene its characteristic
stability.
8. Which type of bond is formed by the side-by-side overlap of two p orbitals?
A) σ bond
B) π bond
C) δ bond
D) Hydrogen bond
Answer: B) π bond
Rationale: A π bond is formed by the sideways (parallel) overlap of two p orbitals. This type
of overlap results in electron density above and below the internuclear axis. In contrast, σ
bonds are formed by head-on overlap of orbitals along the internuclear axis.
9. What is the most important factor in determining the acidity of a compound?
A) Electronegativity of the atom bearing the acidic proton
B) Size of the atom bearing the acidic proton
C) Stability of the conjugate base
D) Polarity of the solvent
Answer: C) Stability of the conjugate base
Rationale: The stability of the conjugate base is the primary factor determining acidity. A
more stable conjugate base corresponds to a stronger acid. Factors that stabilize the
conjugate base include resonance, electronegativity, and polarizability. While the other
factors are relevant, conjugate base stability is the most important overarching principle.
10. Which of the following compounds is the strongest acid?
A) CH₄
B) NH₃
C) H₂O
D) HF
, Answer: D) HF
Rationale: Among these compounds, HF is the strongest acid. While bond strength and
electronegativity are factors, HF dissociates to form the highly stable F⁻ ion. The trend for
acidity in the second period is CH₄ < NH₃ < H₂O < HF, correlating with increasing
electronegativity of the atom bearing the acidic hydrogen.
11. What is the conjugate base of H₂SO₄?
A) HSO₄⁻
B) SO₄²⁻
C) H₂SO₃
D) HSO₃⁻
Answer: A) HSO₄⁻
Rationale: The conjugate base of any acid is formed by removal of a proton (H⁺). When
H₂SO₄ loses one proton, it forms HSO₄⁻ (hydrogen sulfate ion). This species can further lose
a proton to form SO₄²⁻, but the immediate conjugate base of H₂SO₄ is HSO₄⁻.
12. Which of the following correctly describes a Lewis acid?
A) A proton donor
B) A proton acceptor
C) An electron pair acceptor
D) An electron pair donor
Answer: C) An electron pair acceptor
Rationale: According to the Lewis definition, an acid is an electron pair acceptor. This
definition is broader than the Brønsted-Lowry definition, which defines acids as proton
donors. Lewis acids include species with empty orbitals (e.g., BF₃, AlCl₃, metal cations)
that can accept electron pairs from Lewis bases.
13. What is the formal charge on the oxygen atom in a hydroxide ion (OH⁻)?
A) -2
B) -1
C) 0
D) +1
Answer: B) -1
Rationale: The formal charge on an atom is calculated as: valence electrons - (non-
bonding electrons + 1/2 bonding electrons). For oxygen in OH⁻, oxygen has 6 valence
COVERAGE
SECTION A: STRUCTURE, BONDING, AND ACIDS & BASES
1. What is the ground-state electronic configuration of a carbon atom?
A) 1s² 2s² 2p²
B) 1s² 2s² 2p³
C) 1s² 2s¹ 2p³
D) 1s² 2s² 2p⁴
Answer: A) 1s² 2s² 2p²
Rationale: Carbon has atomic number 6. The ground-state configuration follows the
Aufbau principle, with electrons filling the 1s, 2s, and then 2p orbitals sequentially. The
configuration 1s² 2s² 2p² correctly accounts for all six electrons.
2. What is the hybridization state of a carbon atom in a triple bond?
A) sp
B) sp²
C) sp³
D) sp³d
Answer: A) sp
Rationale: A carbon atom involved in a triple bond forms two σ bonds and two π bonds.
This requires two hybrid orbitals for σ bonding, resulting in sp hybridization with a linear
geometry (180° bond angles). The remaining two unhybridized p orbitals form the two π
bonds.
3. Which of the following correctly ranks the indicated bonds in order of increasing
bond strength?
A) C-C < C=C < C≡C
B) C≡C < C=C < C-C
C) C=C < C-C < C≡C
D) C-C < C≡C < C=C
Answer: A) C-C < C=C < C≡C
,Rationale: Bond strength increases with bond order. A single bond (C-C) has the lowest
bond dissociation energy, a double bond (C=C) is stronger, and a triple bond (C≡C) is the
strongest. However, note that the incremental increase is not proportional; the second and
third bonds in multiple bonds are weaker than the first.
4. Which element has the highest electronegativity on the Pauling scale?
A) Oxygen
B) Nitrogen
C) Chlorine
D) Fluorine
Answer: D) Fluorine
Rationale: Fluorine has the highest electronegativity value (4.0) on the Pauling scale. This
is due to its small atomic size and high effective nuclear charge, allowing it to strongly
attract electrons in a chemical bond. Oxygen (3.5), chlorine (3.0), and nitrogen (3.0) are
also highly electronegative but less than fluorine.
5. What is the correct ground-state electronic configuration of a chloride anion (Cl⁻)?
A) 1s² 2s² 2p⁶ 3s² 3p⁵
B) 1s² 2s² 2p⁶ 3s² 3p⁶
C) 1s² 2s² 2p⁶ 3s² 3p⁴
D) 1s² 2s² 2p⁶ 3s² 3p⁶ 4s¹
Answer: B) 1s² 2s² 2p⁶ 3s² 3p⁶
Rationale: A chlorine atom (atomic number 17) has the configuration 1s² 2s² 2p⁶ 3s² 3p⁵.
When chlorine gains one electron to become Cl⁻, it achieves a full octet with the
configuration 1s² 2s² 2p⁶ 3s² 3p⁶, which is isoelectronic with argon.
6. What is the bond angle in a molecule with sp² hybridized carbon?
A) 90°
B) 109.5°
C) 120°
D) 180°
Answer: C) 120°
Rationale: sp² hybridization involves three equivalent hybrid orbitals arranged in a trigonal
planar geometry with bond angles of approximately 120°. This hybridization occurs in
molecules with three electron groups around the central atom, such as alkenes and
carbonyl compounds.
,7. How many π bonds are present in a molecule of benzene (C₆H₆)?
A) 1
B) 2
C) 3
D) 4
Answer: C) 3
Rationale: Benzene has a cyclic structure with alternating single and double bonds. It
contains three π bonds, one for each double bond. However, due to resonance, the π
electrons are delocalized across all six carbon atoms, giving benzene its characteristic
stability.
8. Which type of bond is formed by the side-by-side overlap of two p orbitals?
A) σ bond
B) π bond
C) δ bond
D) Hydrogen bond
Answer: B) π bond
Rationale: A π bond is formed by the sideways (parallel) overlap of two p orbitals. This type
of overlap results in electron density above and below the internuclear axis. In contrast, σ
bonds are formed by head-on overlap of orbitals along the internuclear axis.
9. What is the most important factor in determining the acidity of a compound?
A) Electronegativity of the atom bearing the acidic proton
B) Size of the atom bearing the acidic proton
C) Stability of the conjugate base
D) Polarity of the solvent
Answer: C) Stability of the conjugate base
Rationale: The stability of the conjugate base is the primary factor determining acidity. A
more stable conjugate base corresponds to a stronger acid. Factors that stabilize the
conjugate base include resonance, electronegativity, and polarizability. While the other
factors are relevant, conjugate base stability is the most important overarching principle.
10. Which of the following compounds is the strongest acid?
A) CH₄
B) NH₃
C) H₂O
D) HF
, Answer: D) HF
Rationale: Among these compounds, HF is the strongest acid. While bond strength and
electronegativity are factors, HF dissociates to form the highly stable F⁻ ion. The trend for
acidity in the second period is CH₄ < NH₃ < H₂O < HF, correlating with increasing
electronegativity of the atom bearing the acidic hydrogen.
11. What is the conjugate base of H₂SO₄?
A) HSO₄⁻
B) SO₄²⁻
C) H₂SO₃
D) HSO₃⁻
Answer: A) HSO₄⁻
Rationale: The conjugate base of any acid is formed by removal of a proton (H⁺). When
H₂SO₄ loses one proton, it forms HSO₄⁻ (hydrogen sulfate ion). This species can further lose
a proton to form SO₄²⁻, but the immediate conjugate base of H₂SO₄ is HSO₄⁻.
12. Which of the following correctly describes a Lewis acid?
A) A proton donor
B) A proton acceptor
C) An electron pair acceptor
D) An electron pair donor
Answer: C) An electron pair acceptor
Rationale: According to the Lewis definition, an acid is an electron pair acceptor. This
definition is broader than the Brønsted-Lowry definition, which defines acids as proton
donors. Lewis acids include species with empty orbitals (e.g., BF₃, AlCl₃, metal cations)
that can accept electron pairs from Lewis bases.
13. What is the formal charge on the oxygen atom in a hydroxide ion (OH⁻)?
A) -2
B) -1
C) 0
D) +1
Answer: B) -1
Rationale: The formal charge on an atom is calculated as: valence electrons - (non-
bonding electrons + 1/2 bonding electrons). For oxygen in OH⁻, oxygen has 6 valence
