Organic Chemistry I Examination
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The central atom in most organic compounds is:
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon
Correct Answer: D. Carbon
Rationale: Organic chemistry primarily studies carbon-containing compounds
because carbon can form four stable covalent bonds.
2. The maximum number of covalent bonds carbon can form is:
A. 2
B. 3
C. 4
D. 6
Correct Answer: C. 4
Rationale: Carbon has four valence electrons and can form four covalent bonds to
achieve a stable octet.
3. A covalent bond is formed by:
,A. Transfer of electrons
B. Loss of protons
C. Gain of neutrons
D. Sharing of electrons
Correct Answer: D. Sharing of electrons
Rationale: Covalent bonds involve sharing electron pairs between atoms.
4. The functional group found in alcohols is:
A. Carbonyl
B. Amino
C. Carboxyl
D. Hydroxyl
Correct Answer: D. Hydroxyl
Rationale: Alcohols contain the hydroxyl (-OH) functional group.
5. The general formula for alkanes is:
A. CnH2n
B. CnH2n−2
C. CnHn
D. CnH2n+2
Correct Answer: D. CnH2n+2
Rationale: Alkanes are saturated hydrocarbons containing only single bonds.
6. A hydrocarbon containing only carbon-carbon single bonds is a(n):
A. Alkene
B. Alkyne
C. Aromatic compound
D. Alkane
,Correct Answer: D. Alkane
Rationale: Alkanes contain only single bonds between carbon atoms.
7. The simplest alkane is:
A. Ethane
B. Propane
C. Butane
D. Methane
Correct Answer: D. Methane
Rationale: Methane contains one carbon atom bonded to four hydrogen atoms.
8. The molecular formula of ethane is:
A. CH₄
B. C₂H₄
C. C₃H₈
D. C₂H₆
Correct Answer: D. C₂H₆
Rationale: Ethane is an alkane with two carbons and six hydrogens.
9. Compounds with the same molecular formula but different structures are
called:
A. Isotopes
B. Homologues
C. Radicals
D. Isomers
Correct Answer: D. Isomers
Rationale: Isomers have identical molecular formulas but different arrangements
of atoms.
, 10. Structural isomers differ in their:
A. Number of atoms
B. Element composition
C. Molecular weight
D. Atom connectivity
Correct Answer: D. Atom connectivity
Rationale: Structural isomers contain the same atoms connected in different ways.
11. The hybridization of carbon in methane is:
A. sp
B. sp²
C. sp³
D. sp³
Correct Answer: D. sp³
Rationale: Carbon in methane forms four sigma bonds using sp³ hybrid orbitals.
12. The bond angle around an sp³ carbon atom is approximately:
A. 90°
B. 120°
C. 150°
D. 109.5°
Correct Answer: D. 109.5°
Rationale: sp³ hybridization produces a tetrahedral geometry with 109.5° bond
angles.
13. A double bond between carbon atoms consists of:
Questions and Correct Answers
(Verified Answers) Plus Rationales 2026
Q&A | Instant Download Pdf
1. The central atom in most organic compounds is:
A. Oxygen
B. Nitrogen
C. Hydrogen
D. Carbon
Correct Answer: D. Carbon
Rationale: Organic chemistry primarily studies carbon-containing compounds
because carbon can form four stable covalent bonds.
2. The maximum number of covalent bonds carbon can form is:
A. 2
B. 3
C. 4
D. 6
Correct Answer: C. 4
Rationale: Carbon has four valence electrons and can form four covalent bonds to
achieve a stable octet.
3. A covalent bond is formed by:
,A. Transfer of electrons
B. Loss of protons
C. Gain of neutrons
D. Sharing of electrons
Correct Answer: D. Sharing of electrons
Rationale: Covalent bonds involve sharing electron pairs between atoms.
4. The functional group found in alcohols is:
A. Carbonyl
B. Amino
C. Carboxyl
D. Hydroxyl
Correct Answer: D. Hydroxyl
Rationale: Alcohols contain the hydroxyl (-OH) functional group.
5. The general formula for alkanes is:
A. CnH2n
B. CnH2n−2
C. CnHn
D. CnH2n+2
Correct Answer: D. CnH2n+2
Rationale: Alkanes are saturated hydrocarbons containing only single bonds.
6. A hydrocarbon containing only carbon-carbon single bonds is a(n):
A. Alkene
B. Alkyne
C. Aromatic compound
D. Alkane
,Correct Answer: D. Alkane
Rationale: Alkanes contain only single bonds between carbon atoms.
7. The simplest alkane is:
A. Ethane
B. Propane
C. Butane
D. Methane
Correct Answer: D. Methane
Rationale: Methane contains one carbon atom bonded to four hydrogen atoms.
8. The molecular formula of ethane is:
A. CH₄
B. C₂H₄
C. C₃H₈
D. C₂H₆
Correct Answer: D. C₂H₆
Rationale: Ethane is an alkane with two carbons and six hydrogens.
9. Compounds with the same molecular formula but different structures are
called:
A. Isotopes
B. Homologues
C. Radicals
D. Isomers
Correct Answer: D. Isomers
Rationale: Isomers have identical molecular formulas but different arrangements
of atoms.
, 10. Structural isomers differ in their:
A. Number of atoms
B. Element composition
C. Molecular weight
D. Atom connectivity
Correct Answer: D. Atom connectivity
Rationale: Structural isomers contain the same atoms connected in different ways.
11. The hybridization of carbon in methane is:
A. sp
B. sp²
C. sp³
D. sp³
Correct Answer: D. sp³
Rationale: Carbon in methane forms four sigma bonds using sp³ hybrid orbitals.
12. The bond angle around an sp³ carbon atom is approximately:
A. 90°
B. 120°
C. 150°
D. 109.5°
Correct Answer: D. 109.5°
Rationale: sp³ hybridization produces a tetrahedral geometry with 109.5° bond
angles.
13. A double bond between carbon atoms consists of:
