Question

How does cis and trans isomer differ from one another
(i) Boiling Point
(ii) Melting Point
(iii) Solubility in inert solvents
(iv) All of the above

Answer 1

Hint: The term cis is derived from Latin and it means on the same side. So in the cis isomer, the substituents are placed on the same side of a double bond or a non-aromatic ring. While the term trans is also derived from Latin and it means on opposing sides. So in the trans isomer, the substituents are placed on opposite sides of a double bond plane or a non-aromatic ring. Compare the two structures to know the difference.

Complete step-by-step answer:

Cis Isomer	Trans Isomer
In the cis isomer, the substituents are placed on the same side of a double bond or a non-aromatic ring.	In the trans isomer, the substituents are placed on opposite sides of a double bond plane or a non-aromatic ring.
As the same groups are present on the same side the molecules are polar, which results in an increased intermolecular attractive force between the atoms resulting in a higher boiling point.	As the same groups are present on the opposite sides the dipole moment of one group is cancelled by the other similar group hence the molecules are not as polar as the cis isomer. Due to decreased polarity the attractive forces between the atoms are also reduced hence they have lower boiling point.
As the same groups are present on the same side the molecules are polar, which results in an increased intermolecular attractive force between the atoms resulting in a higher boiling point.	Trans isomers have higher symmetry compared to cis isomers, hence they are tightly packed leading to higher melting point compared to the cis isomers.
Cis isomers are less symmetrical compared to trans isomers, hence they are loosely packed leading to relatively lower melting point.
Generally they have higher solubility in inert solvents.

So we can differentiate cis and trans isomers on the basis of their boiling point, melting point and solubility in inert solvents.

Hence the correct answer is (iv) All of the above.

Note: The most important part of the question is to understand the difference between the structures of cis isomers and the trans isomers. If you are able to understand the difference between the structures of the two isomers you will know how to differentiate them very easily.