Problem 10 - General Chemistry: Principles and Modern Applications

Question

Write a chemical equation for the hydrolysis in alkaline solution of \(\mathrm{XeF}_{6}\) that yields \(\mathrm{XeO}_{6}^{4-}, \mathrm{Xe}, \mathrm{O}_{2}, \mathrm{F}^{-}\) and \(\mathrm{H}_{2} \mathrm{O}\) as products.

Step-by-Step Solution

Answer

The balanced chemical equation for the hydrolysis of \(\mathrm{XeF}_{6}\) that yields \(\mathrm{XeO}_{6}^{4-}, \mathrm{Xe}, \mathrm{O}_{2}, \mathrm{F}^{-}\), and \(\mathrm{H}_{2} \mathrm{O}\) as products is: \(\mathrm{XeF}_{6} + 6\mathrm{OH}^{-} → \mathrm{Xe} + \mathrm{XeO}_{6}^{4-} + \mathrm{O}_{2} + 4\mathrm{F}^{-} + 3\mathrm{H}_{2} \mathrm{O}\).

Step 1: Write the initial reaction

The first step in writing a chemical equation is outlining the reactants and the products. The reactant provided is \(\mathrm{XeF}_{6}\) and the reaction is in an alkaline solution, meaning there is also \(\mathrm{OH}^{-}\) present. This results in the following products: \(\mathrm{Xe}, \mathrm{XeO}_{6}^{4-}, \mathrm{O}_{2}, \mathrm{F}^{-}, \mathrm{H}_{2} \mathrm{O}\). Thus, the initial reaction can be written as: \(\mathrm{XeF}_{6} + n\mathrm{OH}^{-} → \mathrm{Xe} + \mathrm{XeO}_{6}^{4-} + \mathrm{O}_{2} + \mathrm{F}^{-} + \mathrm{H}_{2} \mathrm{O}\)

Step 2: Balance the equation

The second step is to balance the equation by ensuring there is the same number of each atom on both sides of the equation. This can be achieved by adding coefficients (the numbers in front of the reactants or products) accordingly. After inspection, the balanced equation is: \(\mathrm{XeF}_{6} + 6\mathrm{OH}^{-} → \mathrm{Xe} + \(\mathrm{XeO}_{6}^{4-} + \mathrm{O}_{2} + 4\mathrm{F}^{-} + 3\mathrm{H}_{2} \mathrm{O}\)

Step 3: Confirm the equation is balanced

By checking each type of atom separately one can confirm that the equation is balanced, which means having the same number of atoms of each element on both sides of the equation. The final chemical equation is: \(\mathrm{XeF}_{6} + 6\mathrm{OH}^{-} → \mathrm{Xe} + \mathrm{XeO}_{6}^{4-} + \mathrm{O}_{2} + 4\mathrm{F}^{-} + 3\mathrm{H}_{2} \mathrm{O}\)

Key Concepts

Understanding Hydrolysis

Hydrolysis is a chemical process where a molecule reacts with water to break a bond and form two or more new substances. The term comes from 'hydro,' meaning water, and 'lysis,' meaning to break down. In our exercise, hydrolysis of \( \text{XeF}_{6} \) involves an alkaline solution.

• During hydrolysis, \( \text{XeF}_{6} \) reacts with hydroxide ions \( \text{OH}^- \).
• This is typical of reactions in basic conditions, where water and a base like \( \text{NaOH} \) provide \( \text{OH}^- \) ions.
• The products of this hydrolysis are species like \( \text{Xe}, \text{XeO}_{6}^{4-}, \text{O}_{2}, \text{F}^- \), and \( \text{H}_{2} \text{O} \).

This type of reaction helps in breaking down complex molecules into simpler components, especially when a base is present.

Role of Alkaline Solution

An alkaline solution is a key factor in certain chemical reactions, known for its basic, or pH greater than 7, characteristics. In our reaction:

• Alkaline solutions contain \( \text{OH}^- \) ions which are vital for hydrolysis.
• They provide the necessary environment for breaking bonds in \( \text{XeF}_{6} \).
• The presence of these ions ensures the reaction proceeds, supporting the formation of \( \text{Xe, XeO}_{6}^{4-}, \text{O}_{2}, \text{F}^- \), and \( \text{H}_{2} \text{O} \).

The alkaline condition helps facilitate the reaction by making it energetically favorable. This encourages the reactants to transform and form the desired products.

Balancing Chemical Equations

Balancing chemical equations is crucial in ensuring the law of conservation of mass holds, meaning the same number of each type of atom must be present on both sides of a chemical equation. For our given reaction:

• Start by writing the unbalanced equation: \( \text{XeF}_{6} + n\text{OH}^- \, \rightarrow \, \text{Xe} + \text{XeO}_{6}^{4-} + \text{O}_{2} + \text{F}^- + \text{H}_{2} \text{O} \).
• Add coefficients to balance the number of specific atoms on each side.
• The balanced equation becomes: \( \text{XeF}_{6} + 6\text{OH}^- \, \rightarrow \, \text{Xe} + \text{XeO}_{6}^{4-} + \text{O}_{2} + 4\text{F}^- + 3\text{H}_{2} \text{O} \).

This ensures that for every atom that goes into the reaction, a corresponding atom appears in the products, maintaining the balance necessary for accurate chemical representation.

Chemical Equations in Context

A chemical equation is a symbolic representation of a chemical reaction where the reactants are listed on the left, and products on the right. Using symbols and formulas:

• They show the materials involved in a reaction using their chemical symbols, like \( \text{XeF}_{6} \) and \( \text{OH}^- \).
• They highlight molecule or ion relationships and how substances change.
• Coefficients before a formula balance the equation, indicating the quantity of molecules involved.

Chemical equations serve as a tool to predict products, understand the reaction process, and calculate reaction dynamics such as speed and energy changes. Understanding them is fundamental to grasping how and why reactions occur the way they do.