[Ter]

1.) In ethanol, there are covalent bonds, hydrogen bonds and Van Der Waals. Which bonds or forces are broken when ethanol is vaporized?

I was thinking hydrogen bonds only since Van Der Waals will exist between vaporized ethanol too..is it right?

2.) In CH3COOh, all carbon-oxygen bond lengths are equal. True or false.

I drew out the structure and there was one double bond present. Since acetic acid is a resonance hybrid with free pi electron movement, then I thought there will be equal bond lengths with values intermediate between single and double bonds. Is this the answer?

Please help me, I have no answers and would really like to know if I'm right or where I have gone wrong. Thank you so much!

[Hunter2]

The O-H bond is the strongest. So you have hydrogen bridge like in water. Van de waals you also have in gas condition.

The acetic acid answer seems correct to me.

[sjb]

• What about the covalent bonds (you haven't listed them one way or the other)
• Are the carbon-oxygen bonds equivalent in the acid (not the base), c.f. e.g. methyl ethanoate

[Ter]

Thank you!

For one, I know van der waals exist between molecules in liquid and also gases. I was wondering if in becoming a gas, the van der waals forces, as well as hydrogen bonds will break..I am quite sure the covalent bonds won't break when ethanol vaporizes!

For two, I found the answer key. It says that carbon-oxygen bonds in acetic acid are not the same in length!

[fledarmus]

Acetic acid is the protonated form of the compound - in this form, the hydrogen is bonded to one oxygen atom, and there is a double bond on the other. Although the hydrogen atom can move from one oxygen to the other, it is not truly a resonance form - the hydrogen atom must actually move in space, it isn't just movement of bonds. This means the two carbon-oxygen bonds are different and will have different bond lengths.

The acetate anion is a different story - here it is only the bonds and electrons that move, and there really are two resonance forms. For the acetate anion, the two carbon-oxygen bonds are the same length.