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

The amphoteric oxide is \(\mathrm{SnO_2}\) (option c).

Step-by-step solution

Understanding Amphoteric Oxides

Amphoteric oxides are oxides that can react both as an acid and as a base. Such oxides can react with both acids and bases to form salts and water. Identifying properties like these will help determine the correct compound.

Evaluating Each Option

Let's evaluate each option to see if it shows amphoteric behavior: (a) \(\mathrm{CO_2}\) - This is an acidic oxide as it reacts with water to form carbonic acid.(b) \(\mathrm{SiO_2}\) - This is also an acidic oxide and does not display amphoteric properties.(c) \(\mathrm{SnO_2}\) - Tin(IV) oxide is known to show amphoteric nature as it reacts with both acids and bases.(d) \(\mathrm{CaO}\) - This is a basic oxide since it reacts with water to form calcium hydroxide.

Identifying the Amphoteric Oxide

From our evaluation, \(\mathrm{SnO_2}\) is the only oxide that can react with both acids and bases, confirming its amphoteric nature. The other options are either exclusively acidic or basic oxides.

Key concepts

Acidic Oxides

Acidic oxides are fascinating compounds often formed by nonmetals reacting with oxygen. These oxides tend to have oxides of nonmetals and typically react with water to produce acids. For example, carbon dioxide ( CO_2 ) is a well-known acidic oxide, as it dissolves in water to form carbonic acid. This means acidic oxides can act as acids in chemical reactions, reacting easily with bases to form salts and water.
When learning about acidic oxides, it's important to remember:

• They are usually formed from nonmetallic elements.
• They tend to produce acidic solutions when dissolved in water.
• They react with bases to neutralize them and form water and salts.

Understanding these key characteristics can help identify acidic oxides in various chemical reactions.

Basic Oxides

Basic oxides, in contrast to acidic oxides, are typically formed when metals react with oxygen. A classic example of a basic oxide is calcium oxide ( CaO ). This compound reacts with water to form calcium hydroxide, a basic solution. Basic oxides show behavior opposite to that of acidic oxides and react with acids to form salts and water.
Key features of basic oxides include:

• Formation predominately from metallic elements.
• Often produce basic, alkaline solutions when dissolved in water.
• React with acid solutions to neutralize them, also forming salts and water in the process.

Remembering these points will enable the identification of basic oxides during chemical processes and reactions.

Properties of Oxides

Oxides are compounds composed of oxygen and another element. Their properties can vary widely because they can be acidic, basic, or amphoteric in nature. This variety means understanding the properties of oxides can be crucial in predicting their behavior in chemical reactions.
Here are essential properties to know:

• Oxides can be solid, liquid, or gas at room temperature.
• They may exhibit high melting points if they're ionic, like basic oxides.
• Covalent oxides, like acidic oxides, usually have lower melting points.
• Amphoteric oxides, such as SnO_2 , can react with both acids and bases.

Knowing these properties helps explain why some oxides are more reactive than others and how they can be utilized in various chemical challenges.

Reactivity with Acids and Bases

The reactivity of oxides with acids and bases is a defining attribute that determines their classification as acidic, basic, or amphoteric. This interaction can result in the formation of salts and water, and is integral to understanding the behavior of these compounds.
Oxides reacting with acids and bases can be summarized as follows:

• Acidic oxides react with bases to neutralize them, producing a salt and water.
• Basic oxides do the opposite, reacting with acids under similar conditions.
• Amphoteric oxides, like SnO_2 , display versatility by reacting with both acids and bases, showcasing their unique properties.

Mastery of these reactions helps in predicting the outcomes of chemical processes involving different types of oxides. Such knowledge is crucial for everything from industrial applications to ecological solutions.