“Valence Bond Theory” MCQ with Answer Explanation : NEET 2025.

81. The bond angle in water (H₂O) is approximately:
    A. 109.5°
    B. 107°
    C. 104.5°
    D. 90°

Answer: C. 104.5°

Explanation: In water (H₂O), the oxygen atom undergoes sp³ hybridization, and the bond angle is reduced to about 104.5° due to the lone pairs of electrons on oxygen.

82. In VBT, delocalization of electrons is explained by:
    A. Overlap of atomic orbitals
    B. Resonance structures
    C. Hybridization
    D. Bond dissociation energy

Answer: B. Resonance structures

Explanation: Delocalization of electrons in VBT is often explained using resonance, where electrons are shared among multiple atoms across several valid Lewis structures.

83. In benzene (C₆H₆), the hybridization of each carbon atom is:
    A. sp
    B. sp²
    C. sp³
    D. sp³d

Answer: B. sp²

Explanation: In benzene, each carbon atom is sp² hybridized, and the delocalized pi electrons form a conjugated ring system, giving the molecule its planar structure.

84. The bond angle in a molecule of CO₂ is:
    A. 90°
    B. 104.5°
    C. 120°
    D. 180°

Answer: D. 180°

Explanation: In carbon dioxide (CO₂), the central carbon atom is sp hybridized, resulting in a linear structure with a bond angle of 180°.

85. In VBT, the strength of a pi bond is:
    A. Equal to that of a sigma bond
    B. Greater than that of a sigma bond
    C. Less than that of a sigma bond
    D. Dependent on hybridization

Answer: C. Less than that of a sigma bond

Explanation: A pi bond is generally weaker than a sigma bond because it arises from the sideways overlap of p-orbitals, which is less effective than the head-on overlap that forms a sigma bond.

86. The bond order of nitrogen (N₂) is:
    A. 1
    B. 2
    C. 3
    D. 4

Answer: C. 3

Explanation: In nitrogen (N₂), the bond order is 3, meaning the two nitrogen atoms are connected by a triple bond (one sigma and two pi bonds).

87. Which of the following molecules has a tetrahedral structure?
    A. NH₃
    B. H₂O
    C. CH₄
    D. CO₂

Answer: C. CH₄

Explanation: Methane (CH₄) has a tetrahedral structure, as the carbon atom is sp³ hybridized, and the bond angles are 109.5°.

88. In VBT, the bond angle in a molecule depends primarily on:
    A. The number of pi bonds
    B. The number of lone pairs
    C. The hybridization of the central atom
    D. The size of the atoms involved

Answer: C. The hybridization of the central atom

Explanation: The bond angle in a molecule is largely determined by the hybridization of the central atom, which dictates the spatial arrangement of the bonding orbitals.

89. The hybridization of carbon in C₂H₂ is:
    A. sp
    B. sp²
    C. sp³
    D. sp³d

Answer: A. sp

Explanation: In acetylene (C₂H₂), each carbon atom is sp hybridized, resulting in a linear structure with bond angles of 180°.

90. In VBT, the formation of a sigma bond is always due to:
    A. Sideways overlap of orbitals
    B. End-to-end overlap of orbitals
    C. Overlap of d-orbitals
    D. Overlap of pi orbitals

Answer: B. End-to-end overlap of orbitals

Explanation: A sigma bond is formed by the head-on (end-to-end) overlap of atomic orbitals, which results in stronger bonding than a pi bond.