Question

The melting point of lauric acid CH3(CH2)10CO2H is 43°C.

The melting point of stearic acid CH3(CH2)16CO2H is 69°C.

Which of the following statements explains why the melting point of lauric acid is lower than the melting point of stearic acid?


Select only those responses that apply correctly. Select ALL of the responses that apply; otherwise, no credit will be given.

[]Lauric acids has more polar carboxylic acid group than stearic acids.
[]Stearic acid is soluble in water and lauric acid is not soluble in water.
[]The hydrophobic tail of lauric acid is shorter than the hydrophobic tail of stearic acid.
[]The London force interactions are weaker in stearic acid than they are in lauric acid .
[]Stearic acid is a fatty acid, whereas lauric acid is not a fatty acid.

Answer 1

Solution :-

The hydrophobic tail of lauric acid is shorter than the hydrophobic tail of stearic acid

As the number of the carbon in the chain decreases then it decreases the molar mass of the acids

more carbons means higher melting point and less carbons means lower melting point

therefore since the number of carbon in the lauric acid are less than stearic acid

therefore the melting point of the lauric acid is less than stearic acid.

So the correct answer is

The hydrophobic tail of lauric acid is shorter than the hydrophobic tail of stearic acid