Question

Which of the following is more soluble in water?

• A.
• B.
• C. Both (a) and (b) has similar solubility
• D. Cannot be predicted

Answer 1

The correct option is A

Generally like dissolves like. Thus, polar compounds dissolves in polar solvent.
$\text{Solubility in water}\propto \text{Dipole moment}$
In cis-isomers, the same group will locate on the same side of the doubly bonded carbon atoms. So, they will have a resultant dipole moment. Hence, cis-isomer is soluble in water.

In trans-isomers, the same groups will locate on the opposite side of the doubly bonded carbon. Thus, the dipole will get cancel each other and the resultant dipole moment will be zero.

${\mu }_{cis}>{\mu }_{trans}$
$\therefore$
$\text{Solubility of cis-isomer}>\text{Solubility of trans-isomer}$
Here, compound (a) is cis-isomer so it is more soluble in water compare to trans.