Explanation: Steel is an alloy of iron mixed with small quantities of carbon. Iron being a pure metal is soft as the atoms can slip over one another due to the presence of free electrons.
Addition of carbon to iron, makes the iron hard as the carbon hinders the movement of atoms past one another. The tensile strength or resistance to break under applied force for steel gets more as compared to iron.
Well, you would have to be more specific! Sorry I couldn't help you, but if you have the whole question and it is udnerstandable, please repost your question!
