Assuming the following compounds have similar molar masses.Which one should have the highest boiling point?
A)hexane
B)pentanal
C)1-pentanol
D)2-pentanone
E)3-pentanone

Question

Quizplus · Accepted Answer

The compound with the highest boiling point is the one with the strongest intermolecular forces. In this case, we can compare the compounds based on their functional groups. 
Hexane is a nonpolar molecule and only has London dispersion forces, so its boiling point will be lower than the other compounds. 
Pentanal has a polar carbonyl group, which will increase its boiling point compared to hexane but not as much as the compounds containing hydrogen bonding. 
2-pentanone and 3-pentanone also have carbonyl groups, but they are not capable of hydrogen bonding due to the position of the carbonyl group. 
1-pentanol contains a hydroxyl group, which can engage in hydrogen bonding, making it the compound with the highest boiling point.

Assuming the Following Compounds Have Similar Molar Masses