The `AsF_5` molecule is trigonal bipyramidal. The orbitals used by As for hybridisation are

Options

A. `d_(x^(2)-y^(2)),d_(z^(2),s),p_(x,)p_(y)`
B. `d_(xy),s,p_(x),p_(y),p_(z)`
C. `s, p_(x),p_(y),p_(z),d_(z^(2))`
D. `d_(x^(2)-y^(2)),s,p_(x),p_(y),p_(z)`.

Explanation

To determine the orbitals used by arsenic (As) for hybridization in the molecule AsF5, which has a trigonal bipyramidal shape, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Central Atom and Its Valence Electrons**:
- Arsenic (As) is the central atom in AsF5. It is in group 15 of the periodic table, which means it has 5 valence electrons.

2. **Determine the Number of Fluorine Atoms**:
- AsF5 has 5 fluorine (F) atoms bonded to the arsenic atom.

3. **Count the Total Electron Pairs Around the Central Atom**:
- Each F atom forms a single bond with As, contributing to a total of 5 bonding pairs. Since there are no lone pairs on As in this molecule, we have 5 electron pairs.

4. **Determine the Hybridization**:
- The arrangement of 5 electron pairs corresponds to a trigonal bipyramidal geometry. The hybridization that accommodates this geometry is sp³d.

5. **Identify the Orbitals Involved in Hybridization**:
- For sp³d hybridization, the orbitals involved are:
- 1 s orbital
- 3 p orbitals (px, py, pz)
- 1 d orbital (specifically, the dz² orbital)

6. **Conclusion**:
- The orbitals used by arsenic for hybridization in AsF5 are: 1 s orbital, 3 p orbitals (px, py, pz), and 1 d orbital (dz²).

### Final Answer:
The orbitals used by As for hybridization in AsF5 are: **1 s orbital, 3 p orbitals (px, py, pz), and 1 dz² orbital**.

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