Question

Some metal oxides, such as \(\mathrm{Sc}_{2} \mathrm{O}_{3},\) do not react with pure water, but they do react when the solution becomes either acidic or basic. Do you expect \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) to react when the solution becomes acidic or when it becomes basic? Write a balanced chemical equation to support your answer.

Short answer

We expect \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) to react in an acidic environment since it's a basic oxide. The balanced chemical equation for this reaction is: \[\mathrm{Sc}_{2} \mathrm{O}_{3} + 6 \mathrm{H}^{+} \rightarrow 2 \mathrm{Sc}^{3+} + 3 \mathrm{H}_{2} \mathrm{O}\].

Step-by-step solution

Identify the nature of the metal oxide

First, we need to determine whether the given metal oxide, \(\mathrm{Sc}_{2} \mathrm{O}_{3}\), is an acidic oxide or a basic oxide. This can be done by analyzing the position of the metallic element (Scandium, Sc) in the periodic table. Scandium is a metal from Group 3 and thus expected to form basic oxide.

Predict the reaction environment

Since \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) is a basic oxide, it will react in an acidic environment. In an acidic environment, there will be a higher concentration of H+ ions, which will allow the basic oxide to react and neutralize the excess H+.

Write a balanced chemical equation

Now, let's write a balanced chemical equation for the reaction between the basic oxide \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) and an acid, represented here as \(\mathrm{H}^{+}\). Since \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) is a basic oxide, it would react with 6 H+ ions to form 2 Scandium ions and 3 Water molecules: \[\mathrm{Sc}_{2} \mathrm{O}_{3} + 6 \mathrm{H}^{+} \rightarrow 2 \mathrm{Sc}^{3+} + 3 \mathrm{H}_{2} \mathrm{O}\] In this balanced chemical equation, the basic oxide \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) reacts with H+ ions from the acidic environment to produce Scandium ions and water molecules. This supports our prediction that \(\mathrm{Sc}_{2} \mathrm{O}_{3}\) will react in an acidic environment.

Key concepts

Acidic Environment

An acidic environment is characterized by an abundance of hydrogen ions (\( \mathrm{H}^{+} \)) in a solution. These ions are what give acids their sour taste and their ability to turn litmus paper red. In chemistry, an acidic environment can significantly impact how substances interact and react with each other. For example, certain metal oxides like scandium oxide (\( \mathrm{Sc}_{2} \mathrm{O}_{3} \)) react only in the presence of an acidic environment. Why does this happen?

The presence of a high concentration of \( \mathrm{H}^{+} \) ions in the solution can initiate reactions with compounds that are typically stable in neutral water. Basic oxides, such as \( \mathrm{Sc}_{2} \mathrm{O}_{3} \), will react with the excess hydrogen ions to neutralize them, forming water. This is a classic example of a neutralization reaction where the acid and base work to balance each other.

Understanding the role of an acidic environment helps in predicting the behavior of various compounds in different conditions. It's a core concept that underscores many reactions in chemistry, influencing both the speed and the outcome of the reactions.

Basic Oxides

Basic oxides are compounds that react with acids to form salts and water. These compounds generally include metal oxides like \( \mathrm{Sc}_{2} \mathrm{O}_{3} \). The term ‘basic’ in chemistry often implies that the substance can accept protons or neutralize acids.

A key feature of basic oxides is their inability to dissolve in pure water. However, they react actively in acidic environments. For instance, scandium oxide does not react with water, but it readily interacts with acids due to its basic nature.

• When a basic oxide reacts with an acid, the product is typically a salt and water.
• This kind of reaction is known as a neutralization reaction.
• The chemical identity of the salt formed depends on both the metal oxide and the acid involved.

The role of basic oxides in chemical reactions highlights how different substances interact based on their position in the periodic table and their chemical nature. The understanding of basic oxides extends beyond theoretical exercises and is crucial in many practical applications such as materials science and environmental chemistry.

Chemical Reactions

Chemical reactions involve the transformation of substances through the breaking and forming of chemical bonds. In the context of \( \mathrm{Sc}_{2} \mathrm{O}_{3} \), chemical reactions specifically refer to its interaction with an acidic environment.

Every chemical reaction follows some basic rules:

• Conservation of Mass: The mass of reactants equals the mass of products.
• Rearrangement of Atoms: Atoms are rearranged but not destroyed or lost.
• Balance of Equations: Chemical equations must be balanced to reflect equal numbers of each type of atom on both sides of the reaction.

For the reaction of \( \mathrm{Sc}_{2} \mathrm{O}_{3} \) with an acid, the balanced equation is:\[\mathrm{Sc}_{2} \mathrm{O}_{3} + 6 \mathrm{H}^{+} \rightarrow 2 \mathrm{Sc}^{3+} + 3 \mathrm{H}_{2} \mathrm{O}\]This indicates that scandium oxide reacts completely with hydrogen ions, resulting in scandium ions and water. Such reactions illustrate the principles of stoichiometry, allowing chemists to predict amounts of products formed from given reactants. Understanding these fundamentals is crucial in advancing the study and application of chemistry.