Question

Why is glucose soluble in water but cyclohexane is not?

Answer 1

Hint: A polar molecule is produced when one end of the molecule has a higher number of positive charges than the opposite end, resulting in an electrical pole. When a molecule is stated to have a polar bond, the negative charge centre will be on one side, while the positive charge centre will be on the other.

Complete answer:
As we all know water is a polar molecule, "Like dissolves like". As a result, polar molecules or substances capable of forming hydrogen bonds with water molecules will dissolve in water.
Glucose contains five hydroxyl groups ($ - OH$). Therefore, glucose is involved in intermolecular hydrogen bonding with water molecules, so it is readily soluble in water. On the other hand, cyclohexane is a hydrocarbon. Hydrocarbons do not have any polar group, so they cannot make hydrogen bonds with water.

Note: Many covalent or non-polar compounds, such as sugar, carbon dioxide gas, and many alcohols, will dissolve in water, but they will not break down into ions like ionic compounds do. They are essentially broken into smaller parts of the same molecule.