Boiling points......Acetic acid vs. Ethanol

[Toothguy80]

Why does Acetic Acid have a higher boiling point?

a) Acetic acid molecules form dimers which are held together by two hydrogen bonds.
b) The Ethanol molecules form dimers which are held together by two hydrigen bonds.
c) The acetic acid molecules are more closely packaged than the ethanol molecules
d) The acetic acid molecules have more intramolecular bonds.
e) Acetic acid is more soluble than ethanol.

The answer is a, but I chose d because Acetic acid has a carbonyl group and an R-OH group, so I just thought that it had more intramolecular forces. What are intramolecular forces by the way?

Why is the answer a?

---

Members don't see this ad.

 

[JamieMac]

Why does Acetic Acid have a higher boiling point?

a) Acetic acid molecules form dimers which are held together by two hydrogen bonds.
b) The Ethanol molecules form dimers which are held together by two hydrigen bonds.
c) The acetic acid molecules are more closely packaged than the ethanol molecules
d) The acetic acid molecules have more intramolecular bonds.
e) Acetic acid is more soluble than ethanol.

The answer is a, but I chose d because Acetic acid has a carbonyl group and an R-OH group, so I just thought that it had more intramolecular forces. What are intramolecular forces by the way?

Why is the answer a?

I'll assume that you know what dimers are and tell you why d is wrong. The problem with d is the word "intramolecular", which indicates the forces that exist within a molecule (such as the h bonds that exist in secondary...tertiary of nucleic acids and protein molecules). Now if it said intermolecular, you might have an argument, because the intermolecular forces of hydrogen bonding are responsible for high boiling points.

 

[laundry]

To put int another way of saying it, not Mac's wrong, just two ways of explanation might help ya more.

Just because something is held strongly together, doesn't mean it's boiling point is high because boiling point determination is drawn from how strongly are molecules of the compound attracted to each other, not to themselves...