Final answer:
C2H6 (ethane) has the lowest boiling point among C2H6, CH3OH, and CH3F due to having only London dispersion forces, which are the weakest intermolecular forces.
Step-by-step explanation:
The question asks to identify which compound among C2H6 (ethane), CH3OH (methanol), and CH3F (methyl fluoride) has the lowest boiling point. The boiling point of a substance primarily depends on the strength of its intermolecular forces (IMFs).
C2H6 is a nonpolar molecule with only London dispersion forces. CH3OH has a hydroxyl group (-OH) capable of hydrogen bonding, which is a strong IMF. CH3F is a polar molecule and will have both London dispersion forces and dipole-dipole interactions. Among these, CH3OH will have the highest boiling point due to hydrogen bonding, and CH3F will have a higher boiling point than C2H6 due to dipole-dipole interactions. Therefore, C2H6 will have the lowest boiling point because it has the weakest IMF, being limited to only London dispersion forces.
Thus, the order from lowest to highest boiling point is C2H6 < CH3F < CH3OH.