Final answer:
Fat is not water soluble because it contains long chains of nonpolar hydrocarbons that do not interact well with water, unlike salt, sugar, and other carbohydrates which do dissolve in water.
Step-by-step explanation:
Among salt, sugar, fat, and carbohydrates, fat is not water soluble. Water solubility largely depends on the chemical structure of a substance. Salts such as sodium chloride (table salt) are ionic compounds, which usually dissolve in water due to the interaction between the water molecules and the positive and negative ions. Sucrose (table sugar) and other carbohydrates are also soluble in water because they contain hydroxyl groups that can form hydrogen bonds with water molecules.
However, fats, which are a type of lipid, are largely hydrophobic because they contain long chains of nonpolar hydrocarbons that do not interact favorably with water. As a result, fats do not dissolve in water, which makes them distinct from the other substances listed. It is important to note that while these guidelines are general, there can be exceptions based on the specific chemical properties of the substance in question.