The percentage of lanthanides and iron, respectively , in which metal are

Options

A. 50 , 50
B. 75 , 25
C. 90, 10
D. 95, 5

Answer

To solve the question regarding the percentage of lanthanides and iron in mish metal, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Mish Metal**:
- Mish metal is an alloy primarily composed of rare earth elements, particularly lanthanides, and is also known as cerium mish metal.

2. **Composition of Mish Metal**:
- A typical composition of mish metal includes approximately:
- 30% Cerium
- 25% Lanthanum
- Small amounts of Neodymium and Praseodymium
- However, for the purpose of this question, we focus on the total percentage of lanthanides.

3. **Calculating Total Lanthanides**:
- The total percentage of lanthanides can be approximated as follows:
- Cerium (30%) + Lanthanum (25%) = 55% (not considering small amounts of Neodymium and Praseodymium for simplicity).
- However, the transcript mentions that the total percentage of lanthanides is approximately 95%.

4. **Calculating Iron Percentage**:
- The remaining percentage in mish metal is attributed to iron.
- If the total percentage of lanthanides is 95%, then the percentage of iron can be calculated as:
- 100% - 95% = 5%.

5. **Final Composition**:
- Therefore, the final composition of mish metal is:
- Lanthanides: 95%
- Iron: 5%

6. **Selecting the Correct Option**:
- Based on the calculated percentages, we can now compare with the given options:
- Option 1: 50-50 (Incorrect)
- Option 2: 75-25 (Incorrect)
- Option 3: 90-10 (Incorrect)
- Option 4: 95-5 (Correct)

### Conclusion:
The percentage of lanthanides and iron in mish metal is **95% lanthanides and 5% iron**.