Final answer:
Methanol (CH3OH) is the only substance among CF4, BF3, CH3OH, and SiH4 that is a liquid at room temperature, due to hydrogen bonding which confers a higher boiling point.
Step-by-step explanation:
The substance among CF4, BF3, CH3OH, and SiH4 that is a liquid at room temperature is CH3OH, which is methanol.
At room temperature, CF4 (carbon tetrafluoride) and SiH4 (silane) are gases, while BF3 (boron trifluoride) is a gas under standard conditions but can be encountered as a fuming liquid under high pressure or in solution. CH3OH (methanol) is a liquid due to hydrogen bonding between the molecules, which is a stronger intermolecular force than the London dispersion forces present in the other compounds mentioned. These stronger intermolecular forces in methanol result in a higher boiling point compared to CF4, BF3, and SiH4, allowing methanol to remain in the liquid state at room temperature.