Question about alkanols/alkanoic acids. (1 Viewer)

[Divinity_]

 

[Finx]

The MP's/BP's of alkanols is due to the hydrogen bonding between the molecules (as a result of the O-H functional group)
For example, ethanol:
CH3-CH2-O[H <--> O]H-CH2-CH3

The MP's and BP's of alkanoic acids are even higher due to the presence of twice as many hydrogen bonds
For example, ethanoic acid:

........O[H <--> O]=C-CH3
........|....................|
CH3-C=[O <--> H]O

This is VERY hard to explain and draw in a text box reply.. I hope you can understand it (I hardly understand it myself =/). I think there might be a need to describe polarity in the functional groups for the alkanols and alkanoic acids.

Could someone please confirm or polish this answer up?

 

[Pwnage101]

not really 2 H-bonds in alkanoic acids - more like 1 H-bond and 1 dipole-dipole interaction

 

[Trebla]

The carboxylic acid group COOH in an alkanoic acid makes it much more polar than its corresponding OH group in an alkanol due to the presence of an additional polar oxygen which leads to stronger intermolecular forces hence larger BP.