Monazite is source of

Options

A. He
B. Kr
C. Ar
D. both (b) and (c )

Answer

To answer the question "Monazite is a source of," we can follow these steps:

### Step-by-Step Solution:

1. **Identify Monazite**:
- Monazite is a reddish-brown phosphate mineral that contains rare earth metals. It is primarily composed of various rare earth elements, with cerium being the most common.

2. **Composition of Monazite**:
- The mineral has a variable composition, which means it can contain different rare earth elements, including lanthanum and cerium. It also contains trace amounts of silica (SiO2), uranium, and thorium.

3. **Radioactive Elements**:
- Monazite contains uranium (U) and thorium (Th), which are both radioactive. These elements undergo alpha decay, a process in which they emit alpha particles.

4. **Helium Production**:
- During the alpha decay of uranium and thorium, helium is produced as a byproduct. This helium can be extracted from the mineral by heating it.

5. **Conclusion**:
- Therefore, Monazite is primarily a source of helium due to the alpha decay of uranium and thorium present in it.

### Final Answer:
Monazite is a source of **Helium**.

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