Q1: Brittleness induced due to the presence of sulphur in steel can be reduced by adding

ANS:A - manganese

Manganese is a chemical element with the symbol "Mn" and atomic number 25. In the context of steelmaking, manganese serves several important functions:

1. Deoxidation: Manganese is used as a deoxidizer in steelmaking processes. During steel production, oxygen can be introduced into the molten metal, which can lead to the formation of undesirable oxides. Manganese reacts with oxygen to form manganese oxide (MnO), which floats to the surface of the molten metal and can be easily removed, thus helping to deoxidize the steel.
2. Desulfurization: Manganese also acts as a desulfurizing agent in steelmaking. Sulfur is often present in iron ores and can also be introduced during the steelmaking process. Excessive sulfur content in steel can lead to brittleness and reduced mechanical properties. Manganese forms compounds with sulfur, such as manganese sulfide (MnS), which helps to remove sulfur from the steel, thereby reducing the risk of brittleness.
3. Alloying: Manganese is commonly used as an alloying element in steel. When added in appropriate quantities, manganese improves the hardenability, strength, and toughness of steel. It forms solid solutions with iron, contributing to the formation of a fine-grained microstructure and enhancing the mechanical properties of the steel.