Addition of solution of oxalate to an aqueous solution of mixture of `Ba^(2+), Sr^(2+)` and `Ca^(2+)` will precipitate :

Options

A. `Ca^(2+)`
B. `Ca^(2+)` and `Sr^(2+)`
C. `Ba^(2+)` and `Sr^(2+)`
D. All the three

Explanation

To solve the problem of which ions will precipitate when an aqueous solution of oxalate is added to a mixture of \( \text{Ba}^{2+} \), \( \text{Sr}^{2+} \), and \( \text{Ca}^{2+} \), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Ions**: The ions present in the mixture are \( \text{Ba}^{2+} \) (Barium), \( \text{Sr}^{2+} \) (Strontium), and \( \text{Ca}^{2+} \) (Calcium).

2. **Understand the Reaction with Oxalate**: When oxalate ions (\( \text{C}_2\text{O}_4^{2-} \)) are added to the solution, they can react with the metal ions to form metal oxalates.

3. **Solubility of Metal Oxalates**: The oxalates of the alkaline earth metals (which include barium, strontium, and calcium) are generally insoluble in water. This means that when oxalate ions are added to the solution, they will precipitate out as solid metal oxalates.

4. **Write the Precipitation Reactions**:
- For \( \text{Ba}^{2+} \):
\[ \text{Ba}^{2+} + \text{C}_2\text{O}_4^{2-} \rightarrow \text{BaC}_2\text{O}_4 \, (s) \]
- For \( \text{Sr}^{2+} \):
\[ \text{Sr}^{2+} + \text{C}_2\text{O}_4^{2-} \rightarrow \text{SrC}_2\text{O}_4 \, (s) \]
- For \( \text{Ca}^{2+} \):
\[ \text{Ca}^{2+} + \text{C}_2\text{O}_4^{2-} \rightarrow \text{CaC}_2\text{O}_4 \, (s) \]

5. **Conclusion**: Since all three metal ions (barium, strontium, and calcium) form insoluble oxalates with oxalate ions, the addition of oxalate solution will precipitate all three ions.

### Final Answer:
Thus, the correct answer is that the addition of a solution of oxalate to an aqueous solution of the mixture of \( \text{Ba}^{2+} \), \( \text{Sr}^{2+} \), and \( \text{Ca}^{2+} \) will precipitate **all of these ions**.

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