The existance of following ions have no evidence

Options

A. `H_(2)PO_(4)^(-)`
B. `HPO_(4)^(-2)`
C. `PO_(3)^(3-)`
D. `PO_(4)^(-3)`

Answer

To determine which of the given ions has no evidence of existence, we will analyze the provided ions step by step.

### Step 1: Identify the Given Ions
Let's denote the ions as follows:
- Ion A
- Ion B
- Ion C
- Ion D

### Step 2: Analyze the Ions
We need to understand the relationship of these ions with phosphoric acid (H₃PO₄) and phosphorous acid (H₃PO₃):
- H₃PO₄ (Phosphoric acid) can lose hydrogen ions (H⁺) to form:
- H₂PO₄⁻ (Dihydrogen phosphate)
- HPO₄²⁻ (Hydrogen phosphate)
- PO₄³⁻ (Phosphate)

- H₃PO₃ (Phosphorous acid) can lose hydrogen ions to form:
- H₂PO₃⁻ (Dihydrogen phosphite)
- HPO₃²⁻ (Hydrogen phosphite)
- PO₃³⁻ (Phosphite)

### Step 3: Evaluate the Existence of Each Ion
- **Ion A**: If it is a conjugate of H₃PO₄ or H₃PO₃, we can check if it can exist based on the removal of hydrogen ions.
- **Ion B**: Similarly, check if it is a conjugate of H₃PO₄ or H₃PO₃.
- **Ion C**: This ion is derived from H₃PO₃. We need to see if it can exist.
- **Ion D**: Check if it is a conjugate of H₃PO₄ or H₃PO₃.

### Step 4: Determine Which Ion Lacks Evidence
From the analysis, we find that:
- The ions derived from H₃PO₄ (like H₂PO₄⁻, HPO₄²⁻, and PO₄³⁻) are well-documented and exist.
- However, when we analyze the ion that is derived from H₂PO₄⁻, it becomes difficult to remove another hydrogen ion to form HPO₄²⁻ due to the strong attraction between the remaining hydrogen and the negatively charged ion.

### Conclusion
The ion that lacks evidence of existence is **HPO₄²⁻**.

### Summary
- The existence of HPO₄²⁻ is difficult due to the strong attraction between the remaining hydrogen ion and the negatively charged species, making it unlikely to exist.