Which one of the following substances is NOT a mixture?

In chemistry, a pure substance consists of only one type of particle (atoms or molecules) and cannot be separated by physical processes [1]. Ice is the solid form of water (H₂O), which is a chemical compound and thus a pure substance [1]. In contrast, a mixture consists of two or more substances physically combined in variable ratios. Air is a homogeneous mixture of various gases like nitrogen, oxygen, and carbon dioxide. Ice-cream is a complex heterogeneous mixture containing milk, sugar, and air bubbles. Honey is a natural mixture primarily composed of sugars like fructose and glucose along with water. While substances like dry ice or liquid nitrogen are pure substances, common items like air and ice-cream are classified as mixtures because their components retain individual properties and can be separated [1].

Sources

1. [1] Science ,Class VIII . NCERT(Revised ed 2025) > Chapter 8: Nature of Matter: Elements, Compounds, and Mixtures > Snapshots > p. 130