The fluoride ion reacts with water to produce HF. (c) Is fluoride acting as a Lewis acid or as a Lewis base when reacting with water?

Verified step by step guidance

1. Understand the concept of Lewis acids and bases: A Lewis acid is a substance that can accept a pair of electrons, while a Lewis base is a substance that can donate a pair of electrons.
2. Identify the role of fluoride ion (F⁻) in the reaction: The fluoride ion has a lone pair of electrons that it can donate.
3. Consider the reaction between fluoride ion and water: F⁻ + H₂O ⇌ HF + OH⁻.
4. Analyze the interaction: The fluoride ion donates its lone pair of electrons to a hydrogen atom from water, forming HF.
5. Conclude the role of fluoride: Since the fluoride ion donates a pair of electrons, it is acting as a Lewis base in this reaction.

Key Concepts

Lewis Acids and Bases

Lewis acids are substances that can accept an electron pair, while Lewis bases are those that can donate an electron pair. This theory expands the definition of acids and bases beyond the traditional Brønsted-Lowry definitions, allowing for a broader understanding of chemical reactivity. In this context, identifying whether a species acts as a Lewis acid or base is crucial for predicting the outcome of chemical reactions.

Fluoride Ion (F-)

The fluoride ion (F-) is a negatively charged ion formed when fluorine gains an electron. It is a strong Lewis base due to its high electron density, which allows it to readily donate an electron pair to electron-deficient species. Understanding the properties of fluoride is essential for analyzing its behavior in reactions, particularly its interaction with water.

Hydrolysis of Fluoride Ion

When fluoride ions react with water, they undergo hydrolysis, leading to the formation of hydrofluoric acid (HF). This reaction involves the fluoride ion donating an electron pair to a hydrogen ion from water, illustrating its role as a Lewis base. Recognizing this process is key to determining the acid-base behavior of fluoride in aqueous solutions.