Q1: Eutectoid reaction for iron-carbon system occurs at a temperature of __________ °C.

ANS:D - 1493

The value 1493°C is not the correct temperature for the eutectoid reaction in the iron-carbon system. The correct temperature for the eutectoid reaction is approximately 727°C, not 1493°C. At 1493°C, a different transformation occurs in the iron-carbon system known as the melting point of pure iron (also called the melting point of iron or the melting point of alpha iron). This temperature represents the point at which pure iron transitions from its solid state to its liquid state. During this transformation, the crystalline structure of solid iron breaks down as it absorbs heat energy, and the atoms rearrange into a disordered liquid phase. This process continues until all of the solid iron has melted into liquid iron. While the melting point of pure iron is indeed an important temperature in materials science and metallurgy, it does not correspond to the eutectoid reaction in the iron-carbon system. Therefore, the explanation for the value 1493°C as the temperature for the eutectoid reaction is incorrect. The correct temperature for the eutectoid reaction in the iron-carbon system is approximately 727°C.