ANS:B - hard

When sulfur content in pig iron increases, it tends to make the material more brittle. This increased brittleness is primarily due to the formation of iron sulfide (FeS) inclusions within the microstructure of the iron. These inclusions act as points of weakness, initiating cracks and reducing the material's ability to deform plastically before failure. Brittleness is a property characterized by a lack of plastic deformation and a tendency to fracture under stress without significant warning. In materials science, it is often associated with a reduction in ductility and toughness. Ductility refers to a material's ability to deform under tensile stress, typically characterized by the elongation or stretching of the material before fracture. Toughness, on the other hand, is a measure of a material's ability to absorb energy and deform plastically before fracturing. When sulfur levels are high, the presence of iron sulfide inclusions can promote crack initiation and propagation, leading to premature failure of the material. This brittleness makes the iron less suitable for applications where ductility, toughness, and resistance to fracture are important considerations. In summary, increasing sulfur content in pig iron tends to make it more brittle, reducing its ductility, toughness, and overall mechanical performance. Therefore, controlling sulfur levels is crucial in ensuring the quality and suitability of pig iron for various applications.