Which of the following would be classified as a non-electrolyte?

B, sugar, is classified as a non-electrolyte because it does not dissociate into ions when dissolved in water. Non-electrolytes are substances that do not conduct electricity in a solution because they do not produce free-moving ions. Instead, sugar molecules remain intact in solution, preventing electrical conductivity.

In contrast, sodium chloride, potassium sulfate, and calcium carbonate are all electrolytes. These compounds dissociate into ions when dissolved in water, allowing them to conduct electricity. For instance, sodium chloride breaks down into sodium (Na⁺) and chloride (Cl⁻) ions, while potassium sulfate dissociates into potassium (K⁺) and sulfate (SO₄²⁻) ions, and calcium carbonate can dissociate to release calcium (Ca²⁺) and carbonate (CO₃²⁻) ions. This characteristic of electrolytes is crucial in various biological and chemical processes, making the distinction between them and non-electrolytes important in understanding solutions and their properties.