MCAT Question A Day - 3/7/14 - Answer!
Which of the following are arranged in decreasing order of expected dipole moment?
A. F2, Cl2, Br2
B. H2, HBr, HF
C. HF, HBr, H2
D. K, Na, Li
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The correct answer is (C). In choice (C) the electronegativity between the bonded atoms decreases from HF through H2. Note that the answers in choice (D) are atoms, not molecules, so no dipole moment is defined for them. Note also that the dipole moment is zero for each of the homonuclear diatomic molecules in choice (A).