American Chemical Society (ACS) Chemistry Test 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer is sugar because its molecular structure allows it to interact favorably with water molecules. Sugar, or sucrose, consists of multiple hydroxyl (-OH) groups, which are polar and can form hydrogen bonds with water. This strong interaction facilitates the dissolution process, allowing sugar to readily dissolve in water.

In contrast, the other substances listed exhibit characteristics that hinder their solubility in water. Oil and wax are largely composed of nonpolar hydrocarbons, which do not interact well with water and thus remain insoluble. Graphite, while having some polar characteristics due to its layered structure, does not dissolve in water because the interactions between its layers and water molecules aren't sufficient to break apart the strong intermolecular forces holding the graphite layers together. This distinction in polarity and consequent ability to form hydrogen bonds underlines why sugar is soluble in water, while the others are not.