`SF_6` is unreactive towards water because

Options

A. Sulphur has very small size
B. Fluorine is most electronegative element
C. Sulphur shows `+ 6` oxidation state
D. Due to steric hindrance, molecule cannot attack S-atom.

Answer

To explain why SF₆ (sulfur hexafluoride) is unreactive towards water, we can break down the reasoning into the following steps:

### Step 1: Understanding the Structure of SF₆
SF₆ has a molecular structure where a sulfur atom is surrounded by six fluorine atoms. This arrangement forms an octahedral geometry.

**Hint:** Visualize the octahedral structure of SF₆ to understand how the fluorine atoms are positioned around the sulfur atom.

### Step 2: Analyzing the Properties of Fluorine
Fluorine is the most electronegative element, meaning it has a strong tendency to attract electrons. This high electronegativity contributes to the stability of the SF₆ molecule.

**Hint:** Recall that electronegativity affects the reactivity of compounds; however, it is not the sole reason for the unreactivity of SF₆ with water.

### Step 3: Considering the Steric Hindrance
The presence of six fluorine atoms around the sulfur creates significant steric hindrance. Steric hindrance refers to the prevention of reactions due to the spatial arrangement of atoms. In SF₆, the bulky fluorine atoms and their lone pairs create a barrier that prevents water molecules from approaching the sulfur atom.

**Hint:** Think about how the size and arrangement of atoms in a molecule can affect its reactivity with other substances.

### Step 4: Conclusion on Reactivity with Water
Due to the steric hindrance caused by the six fluorine atoms, water molecules cannot effectively approach and react with the sulfur atom in SF₆. As a result, SF₆ remains unreactive towards water.

**Hint:** Consider how steric factors can inhibit chemical reactions, especially in complex molecules like SF₆.

### Final Answer
SF₆ is unreactive towards water primarily due to steric hindrance, which prevents water molecules from attacking the sulfur atom.