Question

The reaction that yields two solid phases on cooling a liquid phase is called

• A. Eutectoid
• B. Peritectoid
• C. Eutectic
• D. Peritectic

Hint:

Eutectic reaction is \(L\rightarrow \alpha+\beta\), where one liquid transforms into two solid phases on cooling.

Answer 1

The Correct Option is C

In phase diagrams, different invariant reactions occur during heating or cooling. A eutectic reaction occurs when one liquid phase transforms into two solid phases on cooling. It can be represented as: \[ L \rightarrow \alpha+\beta. \] Here, \[ L \] represents liquid phase, and \[ \alpha,\ \beta \] represent two different solid phases. Eutectoid reaction is: \[ \text{solid} \rightarrow \text{two solids}. \] Peritectic reaction generally involves: \[ \text{liquid}+\text{solid} \rightarrow \text{new solid}. \] Peritectoid reaction involves two solid phases forming another solid phase. Since the question asks for a reaction that yields two solid phases on cooling a liquid phase, the reaction is: \[ \text{Eutectic}. \]