Methanol (CH3OH) and ethanol (C2H5OH) are miscible because the major intermolecular force for each is H bonding. In some methanol-ethanol solutions, the mole fraction of methanol is higher, but the mass percent of ethanol is higher. What is the range of mole fraction of methanol for these solutions?
Recall: Mole fraction is calculated by:
The problem states that when the mole fraction of methanol is higher, the mass percent of ethanol is higher. The range of the mole fraction is in between the point where moles of ethanol = moles of methanol and the point where the mass of ethanol > mass of methanol.
This means the mole fraction of ethanol ranges from 0.51 to a higher value, which can be approximated by using a mass percent where the mass of ethanol is just slightly greater than that of methanol.