Unsaturated fatty acids have lower melting points than saturated fatty acids because ________.
A)they have fewer hydrogen atoms
B)they have more hydrogen atoms
C)their molecules fit closely together
D)the cis double bonds give them an irregular shape
E)the trans double bonds give them an irregular shape

Question

Quizplus · Accepted Answer

The presence of cis double bonds in unsaturated fatty acids gives them an irregular shape, which prevents them from packing tightly together. This leads to weaker intermolecular forces between the molecules and hence lower melting points. Saturated fatty acids, on the other hand, have straight chains that can pack tightly together, leading to stronger intermolecular forces and higher melting points.

Unsaturated Fatty Acids Have Lower Melting Points Than Saturated Fatty