NEET Chemistry: Dipole moment Practice Questions
15 free multiple-choice questions on Dipole moment (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. The dipole moment of a molecule is determined by the vector sum of individual bond dipoles. If two identical C-Cl bonds are arranged symmetrically about an axis, what is the resulting net molecular dipole moment?
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Correct answer: B — Zero
Due to the symmetry of the arrangement, the individual bond dipoles cancel each other out vectorially, resulting in a net molecular dipole moment of zero.
Q2. In a molecule, the presence of bond dipoles results in a net molecular dipole moment. This phenomenon is fundamentally related to the concept of:
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Correct answer: B — Polarity
The net molecular dipole moment arises from the asymmetry in charge distribution caused by the individual bond dipoles, which defines the molecule's overall polarity.
Q3. A molecule exhibits a non-zero dipole moment. Which geometrical arrangement among the following would generally maximize the magnitude of the dipole moment for a given set of bond dipoles?
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Correct answer: C — Bent
The bent geometry (like in H₂O) allows the bond dipoles to add up effectively, maximizing the net molecular dipole moment. Linear (CO₂) and Trigonal Planar (BF₃) geometries result in cancellation, yielding zero net dipole moment.
Q4. For a molecule to possess a net dipole moment, it must have:
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Correct answer: C — At least one polar bond.
A molecule has a non-zero dipole moment only if its constituent bonds are polar, and these bond dipoles do not cancel out due to molecular symmetry.
Q5. The dipole moment is a vector quantity. If two identical bond dipoles are oriented in the same direction, what is the resulting molecular dipole moment?
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Correct answer: C — Twice the sum of the individual moments
Since the dipole moment is a vector, if the individual dipoles are aligned, their magnitudes add up (vector addition).
Q6. Which of the following statements is true regarding a molecule having zero dipole moment?
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Correct answer: D — The molecule must be perfectly symmetrical.
A molecule has zero net dipole moment if it possesses a high degree of symmetry, resulting in vector cancellation of individual bond moments.
Q7. For a molecule with a linear geometry, the individual bond dipole moments are:
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Correct answer: B — Parallel to each other
In a linear molecule, the bond dipoles lie along the same axis and are therefore parallel to each other.
Q8. Which factor primarily determines the magnitude of the bond dipole moment?
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Correct answer: A — The difference in electronegativity between bonded atoms
The magnitude of the bond dipole moment is directly proportional to the difference in electronegativity between the two bonded atoms.
Q9. If the individual bond dipole moments are vectorially added, what is the condition required for a molecule to exhibit a net zero dipole moment?
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Correct answer: B — The geometry must be perfectly symmetrical
A net zero dipole moment occurs when the individual bond dipoles are oriented such that they perfectly cancel each other out, which happens in highly symmetrical molecular arrangements.
Q10. For a diatomic molecule, the dipole moment is calculated using the formula μ= q × r, where q is the charge separation and r is the internuclear distance. This relationship is based on which principle?
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Correct answer: B — Coulomb's Law
The dipole moment in a diatomic molecule is fundamentally related to the separation of charge (charge separation q) and the distance between the charges (r), which aligns with the principles governing electrostatic interactions like Coulomb's Law.
Q11. Which diatomic molecule has a non-zero dipole moment?
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Correct answer: B — O₂
O₂ is a heteronuclear diatomic molecule, meaning the atoms have different electronegativities, leading to a net molecular dipole moment. H₂ and N₂ are homonuclear and have zero dipole moments.
Q12. Which molecular arrangement generally leads to a non-zero net dipole moment?
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Correct answer: D — Bent (V-shaped)
Bent geometries (like H₂O) result in asymmetric charge distributions, leading to a net molecular dipole moment. Linear and highly symmetric arrangements result in zero net dipole moments due to cancellation.
Q13. In a molecule with a bent geometry, the resulting dipole moment is generally non-zero because:
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Correct answer: A — The bond dipoles do not cancel out
In bent geometries, the bond dipoles do not cancel each other out due to the asymmetrical arrangement of atoms, resulting in a net molecular dipole moment.
Q14. What is the SI unit for the dipole moment of a molecule?
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Correct answer: B — Debye (D)
The dipole moment is the measure of the separation of positive and negative charge and is measured in the unit Debye (D).
Q15. Which molecule among the following exhibits a non-zero net dipole moment?
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Correct answer: C — NH₃
NH₃ (Ammonia) has a trigonal pyramidal geometry with an uneven distribution of electron density, giving it a net molecular dipole moment. CO₂ and CCl₄ are linear and tetrahedral, respectively, and are non-polar (dipole moment = 0).
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