Polyanion formation is maximum in

Options

A. Nitrogen
B. Oxygen
C. Sulphur
D. Boron

Answer

To determine which element has the maximum tendency to form polyanions among the given options (nitrogen, oxygen, sulfur, and boron), we can follow these steps:

### Step-by-Step Solution:

1. **Understand Polyanion Formation**:
- A polyanion is a negatively charged ion that has more than one negative charge. This means the element can attract multiple electrons or share electrons in such a way that it can stabilize multiple negative charges.

2. **Evaluate Each Element**:
- **Nitrogen (N)**:
- Nitrogen typically forms simple anions like nitride (N³⁻) but does not commonly form polyanions with multiple negative charges.
- **Oxygen (O)**:
- Oxygen can form anions like oxide (O²⁻) and peroxides (O₂²⁻), but it does not have a strong tendency to form complex polyanions compared to sulfur.
- **Sulfur (S)**:
- Sulfur is known for its ability to form various polyanions such as sulfide (S²⁻), thiosulfate (S₂O₃²⁻), and polysulfides (e.g., S₄²⁻, S₅²⁻). This indicates a strong tendency to form multiple negative charges.
- **Boron (B)**:
- Boron typically forms covalent compounds and does not exhibit a tendency to form polyanions.

3. **Conclusion**:
- Among the elements evaluated, sulfur has the highest tendency to form polyanions due to its ability to stabilize multiple negative charges through its larger atomic size and the presence of d-orbitals that can participate in bonding.

### Final Answer:
- The element with the maximum tendency to form polyanions is **sulfur**.