Sulphate ion is isostructural with :

Options

A. `PO_(4)^(3-)`
B. `NO_(3)^(-)`
C. `CO_(3)^(2-)`
D. `NO_(2)^(-)`.

Answer

To determine which ion is isostructural with the sulfate ion (SO₄²⁻), we need to analyze the structure and hybridization of the sulfate ion and compare it with other ions.

### Step-by-Step Solution:

1. **Identify the Structure of Sulfate Ion (SO₄²⁻)**:
- The sulfate ion consists of one sulfur atom (S) and four oxygen atoms (O).
- Sulfur has 6 valence electrons, and each oxygen atom has 6 valence electrons.
- The total charge of -2 indicates that there are 2 extra electrons.

2. **Determine the Hybridization of Sulfate Ion**:
- Sulfur forms four bonds with oxygen atoms: two of these bonds are double bonds, and two are single bonds (due to resonance).
- The steric number (number of bond pairs + lone pairs) is 4 (4 bond pairs, 0 lone pairs).
- This gives us an sp³ hybridization.

3. **Identify the Geometry**:
- With an sp³ hybridization and a steric number of 4, the geometry of the sulfate ion is tetrahedral.

4. **Find Other Ions with Similar Structure**:
- We need to look for other ions that also have a tetrahedral structure and sp³ hybridization.
- **Phosphate Ion (PO₄³⁻)**:
- Phosphorus has 5 valence electrons and forms four bonds with oxygen atoms. It also has a tetrahedral structure and sp³ hybridization, making it isostructural with sulfate.
- **Carbonate Ion (CO₃²⁻)**:
- Carbon has 4 valence electrons and forms three bonds with oxygen. However, it has a trigonal planar structure (sp² hybridization), so it is not isostructural.
- **Nitrate Ion (NO₃⁻)**:
- Nitrogen has 5 valence electrons and forms three bonds with oxygen, resulting in a trigonal planar structure (sp² hybridization), so it is not isostructural.
- **Nitrite Ion (NO₂⁻)**:
- Nitrogen forms two bonds with oxygen and has a lone pair, resulting in a bent structure (also not isostructural).

5. **Conclusion**:
- The sulfate ion (SO₄²⁻) is isostructural with the phosphate ion (PO₄³⁻).

### Final Answer:
The sulfate ion (SO₄²⁻) is isostructural with the phosphate ion (PO₄³⁻).