Which member of the following pairs has the larger London dispersion forces?

H2O or H2S

CO2 or CO

CH4 or SiH4

H₂S; CO₂; SiH₄

Explanation:

London dispersion forces are larger in molecules that are large and have more atoms or electrons.

A. H₂O or H₂S

H₂S. S is below O in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.

B. CO₂ or CO

CO₂. CO₂ has more atoms. It is also linear, so the molecules can get close to each other and maximize the attractive forces.

C. CH₄ or SiH₄

CH₄. Si is below C in the Periodic Table, so it is the larger atom. Its electrons are more polarizable.