Question

The dipole moment value of which of the following molecules is maximum?

• A. BeF\(_2\)
• B. H\(_2\)O
• C. NH\(_3\)
• D. CH\(_4\)

Hint:

The dipole moment depends on both bond polarity and molecular geometry. Symmetrical molecules such as \(CH_4\) and \(BeF_2\) have zero net dipole moment because individual bond moments cancel out.

Answer 1

The Correct Option is B

Step 1: Recalling dipole moment fundamentals.
Dipole moment μ = q · r, contingent upon charge separation magnitude and molecular shape.

Step 2: Impact of molecular geometry.
H₂O possesses a bent configuration, causing bond dipoles to vectorially add rather than cancel, yielding a substantial net dipole moment.

Step 3: Evaluating symmetry.
BeF₂ is linear, so its bond dipoles oppose and negate each other, resulting in μ = 0.

Step 4: Considering NH₃.
NH₃ adopts a trigonal pyramidal shape with a net dipole, though smaller than that of water.

Step 5: Considering CH₄.
CH₄ exhibits tetrahedral symmetry where bond dipoles cancel completely, giving μ = 0.

Step 6: Final deduction.
Hence, among these molecules, H₂O has the highest dipole moment.