Question

SiF\(_4\) gets hydrolysed giving

• A. SiO\(_2\)
• B. Si(OH)\(_2\)F\(_2\)
• C. H\(_2\)SiF\(_6\)
• D. Si(OH)\(_4\)

Hint:

SiF\(_4\) with excess HF gives H\(_2\)SiF\(_6\).

Answer 1

The Correct Option is D

The compound silicon tetrafluoride (SiF₄) undergoes hydrolysis when it reacts with water. The process of hydrolysis involves the replacement of fluoride ions with hydroxide ions, leading to the formation of silicic acid, which is Si(OH)₄. The reaction is as follows:

\(SiF_4 + 4H_2O \rightarrow Si(OH)_4 + 4HF\)

Let's break down this reaction:

1. Hydrolysis: When silicon tetrafluoride is mixed with water, it undergoes hydrolysis.
2. Formation of Si(OH)₄: The fluoride ions (F^-) in SiF₄ get replaced by hydroxide ions (OH^-) from water resulting in the formation of silicic acid (Si(OH)₄).
3. By-product: The reaction also results in the formation of hydrofluoric acid (HF) as a by-product.

Now, let's analyze why the answer is Si(OH)₄:

• SiO₂: This is silicon dioxide, which is not a direct product of hydrolysis of SiF₄. However, if Si(OH)₄ is further dehydrated, SiO₂ can be formed, but this is not part of the initial hydrolysis reaction.
• Si(OH)₂F₂: This is not a correct product for the hydrolysis reaction as per standard conditions.
• H₂SiF₆: Known as hexafluorosilicic acid, this compound is not formed in the direct hydrolysis; rather, it forms from fluorosilicic acid complexes in other reactions.
• Si(OH)₄: As explained, this is the correct product formed directly from the hydrolysis of SiF₄.

Therefore, the correct answer to the hydrolysis of SiF₄ is silicon hydroxide, also known as silicic acid, represented as Si(OH)₄.