Question

Which of the following oxides is amphoteric in character? (a) \(\mathrm{CO}_{2}\) (b) \(\mathrm{SiO}_{2}\) (c) \(\mathrm{SnO}_{2}\) (d) \(\mathrm{CaO}\)

Short answer

\(\mathrm{SnO}_{2}\) is amphoteric.

Step-by-step solution

Understanding Amphoteric Oxides

Amphoteric oxides are oxides that can react with both acids and bases. This means that they can form a salt and water by reacting with an acid, and also form a salt and water by reacting with a base.

Evaluating Each Option

Examine each compound to determine if it is amphoteric. (a) \(\mathrm{CO}_{2}\) is acidic, reacting with bases like \(\mathrm{NaOH}\) but not with acids. (b) \(\mathrm{SiO}_{2}\) is also acidic, as it reacts with bases but not with acids. (c) \(\mathrm{SnO}_{2}\) is amphoteric, reacting with both acids and bases. (d) \(\mathrm{CaO}\) is basic, reacting with acids but not with bases.

Conclusion Based on Evaluation

From the evaluation in Step 2, \(\mathrm{SnO}_{2}\) is the only oxide that reacts with both acids and bases, making it amphoteric in character.

Key concepts

Chemical Reactions with Acids and Bases

Chemical reactions involving acids and bases are fundamental in chemistry. Acids are substances that release hydrogen ions ( H^+ ) when dissolved in water, while bases release hydroxide ions ( OH^− ). Acids and bases can neutralize each other, forming salt and water in a reaction known as neutralization. This interaction between hydrogen ions and hydroxide ions to create water is a simple yet powerful concept in solving various chemical equations.
In the context of oxides, these reactions become particularly interesting. Oxides can be classified by how they interact with acids and bases. Some oxides, known as acidic oxides, react with bases. Basic oxides react with acids. The interesting category is the amphoteric oxides, like SnO_2 , which can react with both acids and bases, forming different products in each reaction. It's like having the adaptability of both an acid and a base in a single compound.
This dual capability makes amphoteric oxides very useful in various chemical processes, as they can "switch roles" depending on the reactants they are interacting with. Understanding the behavior of these oxides in chemical reactions is crucial for predicting product formation in both industrial and laboratory settings.

Identification of Oxide Types

Identifying the types of oxides involves understanding their chemical behavior with acids and bases. Oxides can be broadly categorized as:

• Acidic Oxides: These often form when nonmetals react with oxygen. They tend to form acids when reacted with water and react with bases to form salt and water. For example, CO_2 , formed with carbon, is an acidic oxide.
• Basic Oxides: These usually result from metals reacting with oxygen. They typically form bases when reacted with water and react with acids to form salt and water. CaO is a classic example.
• Amphoteric Oxides: These special oxides can act like either acidic or basic oxides. SnO_2 is such an oxide, capable of reacting with both acids and bases to form different products.

Approaching the identification of oxides starts with observing their reactions. For example, an oxide that can react with both hydrochloric acid (an acid) and sodium hydroxide (a base) is amphoteric. Conversely, one that reacts predominantly with one and not the other might either be acidic or basic. Knowing to which category an oxide belongs is invaluable in predicting their behavior in chemical reactions.

Properties of Oxides

Each type of oxide has distinct properties that define its interactions in chemical processes. Understanding these properties helps in recognizing the nature and potential applications of different oxides.
Amphoteric oxides exhibit unique characteristics that bridge the gap between acidic and basic oxides. They contain elements usually found in the center of the periodic table and can demonstrate varied chemical reactivity, adapting based on the surrounding chemical environment. For example, SnO_2 can accept protons ( H^+ ) acting like a base, or donate electrons like an acid, depending on the conditions.
Acidic oxides possess one critical aspect - their capability of reacting more readily with bases to yield salts. These oxides form acidic solutions when combined with water, making them useful in industries focused on acid production.
Basic oxides, on the other hand, primarily form basic (alkaline) solutions in water and are a cornerstone in creating bases. They are prominent in many everyday applications, from neutralizing acidic soils in agriculture to serving in the manufacturing of cement and ceramics.
By exploring the properties of these oxides, we gain insights on their practical uses and how they can transform into different products through chemical reactions, underscoring the intricacy and utility of these fundamental chemical compounds.