Question

Why is the melting point of cis isomers lower?

• A. Better packing of trans isomers
• B. Poorer packing of cis isomers
• C. Better packing of cis isomers
• D. Poorer packing of trans isomers

Answer 1

Answer: (A), (B)

The correct options are
A Better packing of trans isomers
B Poorer packing of cis isomers

Trans isomers pack better than cis isomers. Cis isomers pack poorly, which means that the intermolecular forces aren't as effective as they should be and thus less amount of energy is required to melt the cis molecule. Hence, cis molecules have lower melting point.