CHEM 219 MODULE 1: FOUNDATIONS
OF ORGANIC CHEMISTRY QUESTIONS
WITH CORRECT ANSWERS 2026/2027
UPDATE. JUST RELEASED
1. Which of the following atoms would typically form a trivalent neutral species in organic
molecules?
A. Nitrogen
B. Oxygen
C. Carbon
D. Fluorine
Answer: A
Conceptual Explanation: Nitrogen has 5 valence electrons and typically forms three
covalent bonds to reach an octet, leaving one lone pair, making it trivalent.
2. In the Lewis structure for the chlorate ion (ClO3-), how many lone pairs are on the central
chlorine atom if it obeys the octet rule?
A. 1
,B. 0
C. 2
D. 3
Answer: A
Conceptual Explanation: Chlorine provides 7 valence electrons, three oxygens provide 18,
plus 1 for the charge (26 total). After forming three single bonds to O (6 electrons) and
filling O octets (18 electrons), 2 electrons remain as a lone pair on Cl.
3. Which molecule possesses a net dipole moment of zero?
A. NH3
B. CHCl3
C. H2O
D. BF3
Answer: D
Conceptual Explanation: BF3 has a trigonal planar geometry with three equal B-F bond
dipoles that cancel each other out, resulting in a nonpolar molecule.
4. What is the hybridization of the central carbon atom in allene (H2C=C=CH2)?
A. sp3
B. sp2
, C. p
D. sp
Answer: D
Conceptual Explanation: The central carbon is bonded to two other carbons via double
bonds and has no lone pairs, requiring two hybrid orbitals, which corresponds to sp
hybridization.
5. Which of the following is the strongest acid?
A. CH3CH2OH
B. CF3CH2OH
C. CF3COOH
D. CH3COOH
Answer: C
Conceptual Explanation: Trifluoroacetic acid is the strongest due to the presence of three
highly electronegative fluorine atoms which stabilize the conjugate base via the inductive
effect, combined with resonance stabilization of the carboxylate.
6. What is the formal charge on the nitrogen atom in the nitromethane molecule (CH3NO2)?
A. -1
B. 0
C. +2
OF ORGANIC CHEMISTRY QUESTIONS
WITH CORRECT ANSWERS 2026/2027
UPDATE. JUST RELEASED
1. Which of the following atoms would typically form a trivalent neutral species in organic
molecules?
A. Nitrogen
B. Oxygen
C. Carbon
D. Fluorine
Answer: A
Conceptual Explanation: Nitrogen has 5 valence electrons and typically forms three
covalent bonds to reach an octet, leaving one lone pair, making it trivalent.
2. In the Lewis structure for the chlorate ion (ClO3-), how many lone pairs are on the central
chlorine atom if it obeys the octet rule?
A. 1
,B. 0
C. 2
D. 3
Answer: A
Conceptual Explanation: Chlorine provides 7 valence electrons, three oxygens provide 18,
plus 1 for the charge (26 total). After forming three single bonds to O (6 electrons) and
filling O octets (18 electrons), 2 electrons remain as a lone pair on Cl.
3. Which molecule possesses a net dipole moment of zero?
A. NH3
B. CHCl3
C. H2O
D. BF3
Answer: D
Conceptual Explanation: BF3 has a trigonal planar geometry with three equal B-F bond
dipoles that cancel each other out, resulting in a nonpolar molecule.
4. What is the hybridization of the central carbon atom in allene (H2C=C=CH2)?
A. sp3
B. sp2
, C. p
D. sp
Answer: D
Conceptual Explanation: The central carbon is bonded to two other carbons via double
bonds and has no lone pairs, requiring two hybrid orbitals, which corresponds to sp
hybridization.
5. Which of the following is the strongest acid?
A. CH3CH2OH
B. CF3CH2OH
C. CF3COOH
D. CH3COOH
Answer: C
Conceptual Explanation: Trifluoroacetic acid is the strongest due to the presence of three
highly electronegative fluorine atoms which stabilize the conjugate base via the inductive
effect, combined with resonance stabilization of the carboxylate.
6. What is the formal charge on the nitrogen atom in the nitromethane molecule (CH3NO2)?
A. -1
B. 0
C. +2
