Arrange the following fatty acids from highest melting point to lowest melting point. Select all of the following statements about fatty acid melting points that are true.
Is this correct? Why?
Concepts and reason
The concepts used to solve this problem are melting point, molecular weight, saturated and unsaturated fatty acids.
As the molecular weight of the fatty acids is increased, its melting point also increases.
Fundamentals
A fatty acid is defined as a long aliphatic chain (saturated or unsaturated) of carboxylic acid as a functional group. Naturally occurring fatty acids are generally having an un-branched carbon chains in even numbers from 4 to 28. Commercially, fatty acids are derivatives of either triglycerides or phospholipids. Molecular mass of the compound is defined as the sum of the individual atomic masses of its constituent elements multiplied by the number of atoms of the element present in the compound. Melting pointis defined as the temperature at which the solid changes its physical state to a liquid at atmospheric pressure.
Answer:
Part 2.1
A saturated fatty acid with a greater molar mass has a lower melting point than a saturated fatty acid with lower molar mass.
The above statement is false.
Part 2.2
A saturated fatty acid has a lower melting point than an unsaturated fatty acid.
The above statement is false.
Part 2.3
A saturated fatty acid with a greater molar mass has a higher melting point than a saturated fatty acid with lower molar mass.
This statement is true.
Part 2.4
A saturated fatty acid has a higher melting point than an unsaturated fatty acid.
This statement is true.
