Which of the following statements are correct about sulphur hexafluoride ?

Options

A. all S-F bonds are equivalent
B. `SF_(6)` is a planar molecule
C. oxidation number of sulphur is the same as number of electrons of sulphu involved in bonding
D. sulphur has acquired the elctronic structure of the gas argon

Answer

To determine which statements about sulfur hexafluoride (SF6) are correct, we will analyze each statement step by step.

### Step 1: Determine the Hybridization and Structure of SF6
1. **Identify the central atom**: The central atom in SF6 is sulfur (S).
2. **Count the valence electrons**: Sulfur has 6 valence electrons, and each fluorine (F) atom has 7 valence electrons. Since there are 6 fluorine atoms, the total number of valence electrons contributed by fluorine is \(6 \times 7 = 42\).
3. **Calculate the steric number**: The steric number is calculated using the formula:
\[ \text{Steric Number} = \frac{1}{2} \left( \text{Number of valence electrons of central atom} + \text{Number of monovalent atoms} \right) \]
Here, the number of valence electrons of sulfur is 6, and there are 6 fluorine atoms (monovalent). Thus:
\[ \text{Steric Number} = \frac{1}{2} (6 + 6) = \frac{12}{2} = 6 \]
4. **Determine hybridization**: A steric number of 6 corresponds to \(sp^3d^2\) hybridization.
5. **Determine molecular geometry**: With 6 bond pairs and no lone pairs, the geometry is octahedral.

### Step 2: Analyze Each Statement
1. **Statement 1**: "All SF bonds are equivalent."
- **Analysis**: True. In an octahedral structure, all SF bonds are equivalent due to symmetry.

2. **Statement 2**: "SF6 is a planar molecule."
- **Analysis**: False. SF6 is octahedral, which is not planar as it has bonds in three-dimensional space.

3. **Statement 3**: "The oxidation number of sulfur is the same as the number of electrons of sulfur involved in bonding."
- **Analysis**: True. The oxidation state of sulfur in SF6 is +6 (calculated as \(X + 6(-1) = 0\), where \(X\) is the oxidation state of sulfur). Since sulfur is involved in 6 bonds, the number of bonding electrons is also 6.

4. **Statement 4**: "Sulfur has acquired the electronic structure of the gas argon."
- **Analysis**: False. Argon has 18 electrons, while sulfur in SF6 has 12 valence electrons from bonding and 10 inner electrons, totaling 22 electrons, which does not match argon's electronic configuration.

### Conclusion
The correct statements about sulfur hexafluoride (SF6) are:
- Statement 1: True
- Statement 2: False
- Statement 3: True
- Statement 4: False

Thus, the correct answers are **1 and 3**.

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