5.2.3 (1 Viewer)

[kimmeh]

explain the difference in melting point and boiling point caused by straight-chained alkanoic acid and straight-chained primary alkanol structures

hmm could i say that because of the double bond, the alknaoic acid has ahigher BP and MP ?

 

[CM_Tutor]

No, alkanoic acids have higher MP / BP than their alkanol equivakents, as they have more hydrogen bonding - just like the reason BP(H₂O) > BP(NH₃).

 

[kimmeh]

ahaha i figured it out .. thanks CM tutor..
the alkanol has like 2 intermolecular hydrogen bonds, the alkanoic acid has 4 and the ester has none

 

[felafel]

Originally posted by kimmeh
ahaha i figured it out .. thanks CM tutor..
the alkanol has like 2 intermolecular hydrogen bonds, the alkanoic acid has 4 and the ester has none

you shouldn't write "it has 2 or 4 intermolecular bonds" - you should write it has the POTENTIAL to form more intermolecular bonds

 

[xiao1985]

true that... but u can write it has n number of hydrogen bond, hence making it easier to have stronger intermolecular interactions