Chemistry help!! Boiling points of carboxylic acids, alcohols and aldehydes

The question is:

Predict which one of the compounds: propan-1-ol, propanal and propanoic acid will have the highest boiling point. Explain your answer.

I know that it's between the alcohol and acid cos of hydrogen bonds but how do you know which will be higher?
Please help!!! When I answered this question I put propan-1-ol and my teacher marked it right but the mark scheme says the answer is propanoic acid and now I'm really confused!!!! Which one is right?!
Thanks in advance xxx


Posted from TSR Mobile

The acid because it can make double the number of hydrogen bonds. If in doubt just look it up.

http://en.wikipedia.org/wiki/Propanoic_acid 141ºC
http://en.wikipedia.org/wiki/1-Propanol 98ºC

How would you explain it


Posted from TSR Mobile

I wonder why my teacher gave me credit for my original answer!

So would the correct answer be:
-propanoic acid
-hydrogen bonding
-the intermolecular forces within propanoic acid are stronger than in propanol because hydrogen bonds can also form between the oxygen of the c=o and the hydrogen on the o-h of a neighbouring molecule


Posted from TSR Mobile

Carboxylic acids also exist as dimers in the vapour phase with each pair being held together by two hydrogen bonds.