Partially molten iron can be categorized as a mixture. In this state, it contains both solid iron and liquid iron, creating two distinct phases: the solid phase (solid iron particles) and the liquid phase (molten iron). This combination of solid and liquid materials is what qualifies it as a mixture rather than a pure substance.
A pure substance consists of a single type of particle, whereas a mixture comprises multiple substances that retain their individual properties. Since partially molten iron has both solid and liquid components, it does not meet the criteria to be classified as a pure substance.
In summary, the presence of both solid and liquid phases in partially molten iron makes it a mixture, highlighting the distinct characteristics of each phase involved.