Which one of the following metals is alloyed with sodium to transfer heat in a nuclear reactor ?

Options

A. Potassium
B. Calcium
C. Magnesium
D. Strontium

Explanation

**Step-by-Step Solution:**

1. **Understanding the Context**: In a nuclear reactor, heat transfer is crucial for maintaining the reactor's operational efficiency and safety. The choice of materials for heat transfer is important.

2. **Identifying the Metals**: The question asks which metal is alloyed with sodium. Sodium is known to be used as a coolant in some types of nuclear reactors due to its excellent thermal conductivity.

3. **Researching Suitable Metals**: Among the metals that can be alloyed with sodium, potassium (K) is a well-known option. Potassium is a soft, highly reactive metal that can be alloyed with sodium.

4. **Properties of Potassium**: Potassium has properties that make it suitable for use in a sodium alloy. Its reactivity and physical characteristics allow it to effectively transfer heat.

5. **Conclusion**: The metal that is alloyed with sodium to transfer heat in a nuclear reactor is potassium.

**Final Answer**: Potassium (K) is the metal alloyed with sodium to transfer heat in a nuclear reactor.

---