In liquid ammonia, molecules form extensive hydrogen-bonded networks. A student argues that liquid methane (CH₄) should exhibit similar hydrogen bonding because methane also contains hydrogen atoms.
Respond to the student’s claim.
(a) Describe the structural and electronic criteria that must be met for a hydrogen bond to form between two molecular sites.
(b) Using electronegativity arguments and any relevant partial charges, explain why NH₃ molecules meet these criteria whereas CH₄ molecules do not, even though both contain hydrogen.
(c) Predict how replacing one hydrogen in CH₄ with fluorine to give CH₃F would affect the compound’s ability to participate in hydrogen bonding, and justify your prediction.