NEET Chemistry: Molecular Orbital Theory Practice Questions
13 free multiple-choice questions on Molecular Orbital Theory (Chemical Bonding and Molecular Structure) for NEET Chemistry, each with the correct answer and a step-by-step explanation. Attempt a question, then reveal the solution to check your reasoning.
Practice thousands more NEET questions in the app →Q1. According to the Pauli exclusion principle, the maximum number of electrons that can be accommodated in a molecular orbital is determined by:
Show answer & explanation
Correct answer: C — twice the number of atomic orbitals
The Pauli exclusion principle dictates that no two electrons in an atom can have the same set of quantum numbers. This means each molecular orbital can hold a maximum of two electrons (one spin up, one spin down).
Q2. Which molecular orbitals are generally formed by the head-on overlap of s-orbitals, leading to the formation of a cylindrical symmetry around the internuclear axis?
Show answer & explanation
Correct answer: D — σ MOs
The head-on overlap of s-orbitals results in the formation of σ molecular orbitals, which are cylindrically symmetric around the internuclear axis.
Q3. The molecular orbital theory predicts that the bond formed by the overlap of p orbitals results in which type of bond?
Show answer & explanation
Correct answer: B — Purely pi bond
The overlap of p orbitals leads to the formation of π molecular orbitals, which contribute to the overall bond strength alongside the σ interaction.
Q4. In the formation of molecular orbitals, the interaction between atomic orbitals occurs via:
Show answer & explanation
Correct answer: A — overlap of wave functions
The formation of MOs relies on the spatial overlap of the atomic orbitals, which leads to the constructive and destructive interference described by the Linear Combination of Atomic Orbitals (LCAO) method.
Q5. In the formation of molecular orbitals from atomic orbitals, which set of atomic orbitals combines to form a π molecular orbital?
Show answer & explanation
Correct answer: B — p and p
Pi (π) molecular orbitals arise from the side-by-side overlap of p atomic orbitals, which results in two degenerate π orbitals (one bonding and one antibonding).
Q6. In Molecular Orbital Theory (MOT), which type of molecular orbital is formed by the linear combination of atomic orbitals (LCAO) where the signs of the contributing atomic orbitals are the same (constructive interference)?
Show answer & explanation
Correct answer: D — Sigma (σ)
Sigma (σ) molecular orbitals are formed by the constructive interference of atomic orbitals along the internuclear axis, resulting in a node-less orbital.
Q7. Which set of atomic orbitals combine to form molecular orbitals in a diatomic molecule?
Show answer & explanation
Correct answer: D — s and p orbitals
Molecular orbitals are formed by the linear combination of atomic orbitals (LCAO) of the constituent atoms. For diatomic molecules, this typically involves s and p orbitals.
Q8. According to Hund's rule, when electrons occupy degenerate orbitals (orbitals of equal energy), they must be distributed in a manner that maximizes the total spin multiplicity. Which rule primarily governs this distribution?
Show answer & explanation
Correct answer: A — Hund's Rule
Hund's rule states that electrons will singly occupy degenerate orbitals with parallel spins before pairing up, thus maximizing the total spin.
Q9. Which type of molecular orbital (MO) is formed by the side-by-side combination of atomic orbitals (AOs) with the same phase (in-phase combination)?
Show answer & explanation
Correct answer: D — Sigma (σ)
Sigma (σ) orbitals are formed by the end-on overlap of AOs, resulting in a nodal plane passing through the internuclear axis.
Q10. For a bond composed entirely of π bonds, the resulting molecular orbital character is predominantly:
Show answer & explanation
Correct answer: D — antibonding
π bonds arise from the side-by-side overlap of p-orbitals. These interactions result in bonding molecular orbitals (lower energy) and antibonding molecular orbitals (higher energy).
Q11. Which type of molecular orbital arises from the end-on overlap of atomic orbitals along the internuclear axis?
Show answer & explanation
Correct answer: C — σ orbital
Sigma (σ) molecular orbitals are formed by the end-on overlap of atomic orbitals along the internuclear axis, resulting in a nodal plane passing through the nuclei.
Q12. In the molecular orbital theory, according to Hund's rule, electrons will preferentially occupy orbitals of equal energy with which multiplicity?
Show answer & explanation
Correct answer: B — Maximum number of unpaired electrons
Hund's rule states that electrons will singly occupy degenerate orbitals (orbitals of equal energy) with parallel spins to maximize the total spin multiplicity, thus maximizing the number of unpaired electrons.
Q13. The molecular orbitals formed from the side-by-side overlap of p-orbitals are primarily characterized by which type of interaction?
Show answer & explanation
Correct answer: A — Pi interaction
The side-by-side overlap of p-orbitals results in the formation of π molecular orbitals, which correspond to pi interactions.
Keep going — practice on Padhai Karlo
Padhai Karlo gives you unlimited NEET practice: chapter-wise questions, timed quizzes, and full mock tests with an All-India Rank — free to start.
Get the free Android app →