Question

Which one of the following reason is responsible for lower melting point of cis isomer than trans-isomer?

• A. better packing of trans isomers
• B. better packing of cis isomers
• C. poorer packing of trans isomers
• D. both (a) and (b)

Answer 1

The correct option is A better packing of trans 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.