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

11. In a molecule of ethene (C₂H₄), the carbon atoms are:
    A. sp hybridized
    B. sp² hybridized
    C. sp³ hybridized
    D. Not hybridized

Answer: B. sp² hybridized

Explanation: In ethene (C₂H₄), each carbon atom is sp² hybridized, which results in a trigonal planar arrangement. One p-orbital on each carbon atom remains unhybridized, forming a pi bond between them.

12. What type of bond is formed in ethyne (C₂H₂)?
    A. Two sigma bonds and two pi bonds
    B. Three sigma bonds and one pi bond
    C. One sigma bond and two pi bonds
    D. One sigma bond and one pi bond

Answer: A. Two sigma bonds and two pi bonds

Explanation: In ethyne (C₂H₂), each carbon forms one sigma bond with hydrogen and one sigma bond with the other carbon. The remaining p-orbitals overlap to form two pi bonds, making a triple bond between the carbon atoms.

13. According to VBT, the shape of a BF₃ molecule is:
    A. Linear
    B. Trigonal planar
    C. Tetrahedral
    D. Bent

Answer: B. Trigonal planar

Explanation: Boron in BF₃ is sp² hybridized, leading to a trigonal planar shape with bond angles of 120°.

14. The bond angle in methane (CH₄) is:
    A. 90°
    B. 104.5°
    C. 107°
    D. 109.5°

Answer: D. 109.5°

Explanation: Methane (CH₄) has a tetrahedral geometry due to sp³ hybridization of carbon, which results in bond angles of 109.5°.

15. Which of the following molecules does not involve hybridization of the central atom?
    A. H₂O
    B. CH₄
    C. CO₂
    D. O₂

Answer: D. O₂

Explanation: The oxygen molecule (O₂) involves a double bond with no hybridization since there is no central atom. In contrast, H₂O, CH₄, and CO₂ involve hybridization of the central atom.

16. In a PCl₅ molecule, phosphorus exhibits which type of hybridization?
    A. sp³
    B. sp³d
    C. sp²
    D. sp³d²

Answer: B. sp³d

Explanation: Phosphorus in PCl₅ undergoes sp³d hybridization, which leads to a trigonal bipyramidal geometry with 90° and 120° bond angles.

17. In Valence Bond Theory, overlap of atomic orbitals is essential because:
    A. It helps distribute electrons evenly across the molecule
    B. It leads to the formation of molecular orbitals
    C. It results in the pairing of electrons between atoms
    D. It is responsible for ion formation

Answer: C. It results in the pairing of electrons between atoms

Explanation: VBT describes bonding as the result of the overlap of atomic orbitals, leading to the pairing of electrons between atoms to form covalent bonds.

18. In Valence Bond Theory, why does H₂O have a bent structure?
    A. Due to the sp hybridization of oxygen
    B. Because of lone pair-lone pair repulsion
    C. Due to bond pair-bond pair repulsion
    D. Because oxygen does not hybridize

Answer: B. Because of lone pair-lone pair repulsion

Explanation: The bent shape of water is a result of two lone pairs on oxygen repelling the bonded pairs, leading to a reduction in bond angles from 109.5° (ideal tetrahedral) to about 104.5°.

19. What is the hybridization of the central atom in CO₂?
    A. sp
    B. sp²
    C. sp³
    D. sp³d

Answer: A. sp

Explanation: In CO₂, the carbon atom is sp hybridized, resulting in a linear structure with bond angles of 180°.

20. Which of the following molecules does not exhibit sp³ hybridization?
    A. CCl₄
    B. NH₃
    C. H₂O
    D. BeCl₂

Answer: D. BeCl₂

Explanation: BeCl₂ is sp hybridized and has a linear geometry, whereas CCl₄, NH₃, and H₂O exhibit sp³ hybridization.