Carboxylic Acids - Properties

Question 1

Describe the relationship between boiling points of carboxylic acids and their size

Answer 1

Boiling point increases with size

Question 2

Describe the relationship between the melting points and the size of carboxylic acids.
(3)

Answer 2

Melting point does not increase in a regular manner with size

Acids with an even number of C atoms have melting points higher than than of those with odd numbers of C atoms

Cis enoic acids have significantly lower melting point values

Question 3

Why do acids with an even number of C atoms have melting points higher than than of those with odd numbers of C atoms?

Answer 3

This is due to differences in intermolecular attractive forces in the crystalline state and changes in crystal packing

Question 4

Why do carboxylic acids have exceptionally high boiling points?

Answer 4

Due to dimeric associations involving two H-bonds between 2 molecules