Question

You have developed a promising anti-cancer agent, but it has poor solubility in water. Which of the following changes should improve water solubility?

A.
adding a methyl group
B.
adding a hydroxyl group
C.
adding a carboxyl group
D.
increasing the size of the drug
E.
adding a benzene ring

Answer 1

B and C

Step-by-step explanation:

You want your compound to be polar since water is polar and like dissolves like. Methyl groups and benzene rings are not polar so adding them will not help. Increasing the size will not help either because the smaller the solute the more likely it will dissolve (the relationship between size and solubility is inversely proportional). The answer is hydroxyl group and carboxyl group because both are polar.

Answer 2

The correct options is B.

Step-by-step explanation:

Adding a hydroxyl group to the anti-cancer agent will increase its ability to dissolve in water. This is because hydroxyl (OH) group is a functional group that contain oxygen. The oxygen atom present in OH group readily form chemical bond with the hydrogen atoms of water; this increase the solubility of the substance in water.

Another functional group that behave in the same way with OH group is the carbonlyl group, this functional group also has the ability to increase solubility of substances in water. Carbohydrates generally are soluble in water because their structures are made up of both hydroxyl and carbonyl groups.