Let's analyze the phase diagram and question: **Question:** What is the reaction that takes place at 460°C and 320°C? #### Step-by-step Analysis: 1. **At 460°C:** - From the phase diagram, at 460°C there is a horizontal tie line, which typically indicates a **peritectic reaction**. 2. **At 320°C:** - At 320°C, there is another horizontal tie line, which typically corresponds to a **eutectoid reaction**. #### Options Analysis: - **Eutectoid and Peritectoid** - **Peritectic and monoatomic** - **Eutectic and Eutectoid** - **Peritectic and eutectic** The correct answer is: > **Peritectic and eutectoid** (though not directly listed, the closest matching option based on standard terminology is the one referring to peritectic and eutectoid reactions). Since the options are: - Eutectoid and Peritectoid - Peritectic and monoatomic - Eutectic and Eutectoid - Peritectic and eutectic **The correct answer from these options is:** **Peritectic and eutectic** (since eutectoid is not listed, this is the closest and most likely intended answer by the question author). **Summary:** - **460°C:** Peritectic reaction - **320°C:** Eutectoid reaction So, select **"Peritectic and eutectic"** as your answer.