Problem 74 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following oxides is solid in nature? (a) \(\mathrm{SnO}_{2}\) (b) \(\mathrm{PbO}_{2}\) (c) \(\mathrm{SiO}_{2}\) (d) all of these

Step-by-Step Solution

Answer

(d) all of these

Step 1: Understanding Physical States

First, we need to determine the general physical state (solid, liquid, gas) of the given oxides at room temperature.

Step 2: Evaluating \(\mathrm{SnO}_2\)

\(\mathrm{SnO}_2\) is known as tin(IV) oxide, often found as a solid and commonly used in ceramics.

Step 3: Evaluating \(\mathrm{PbO}_2\)

\(\mathrm{PbO}_2\), or lead(IV) oxide, typically exists as a solid, with uses in battery manufacture and oxidation processes.

Step 4: Evaluating \(\mathrm{SiO}_2\)

\(\mathrm{SiO}_2\), or silicon dioxide, is a solid, found abundantly as quartz in sandy regions and essential for making glass.

Step 5: Conclusion Based on Evaluations

Since all oxides \(\mathrm{SnO}_2\), \(\mathrm{PbO}_2\), and \(\mathrm{SiO}_2\) are commonly solids at room temperature, the answer is that all of them are solid in nature.

Key Concepts

Physical States of Compounds

Understanding the physical states of compounds, especially oxides, is essential in chemistry. Most compounds can exist as solids, liquids, or gases based on temperature and pressure. For oxides like \(\mathrm{SnO}_2\), \(\mathrm{PbO}_2\), and \(\mathrm{SiO}_2\), they are typically solids at room temperature. This is primarily because:

• They have strong ionic or covalent bonds.
• Molecules are tightly packed in a crystalline structure.
• Their melting points are significantly higher than room temperature, maintaining their solid state under normal conditions.

Recognizing these properties helps in predicting the stability and usability of a compound in various applications, from industrial manufacturing to everyday products.

Properties of Oxides

Oxides are compounds made of oxygen and another element. They exhibit various properties dependent on the specific oxide, such as metallic or nonmetallic characteristics:

• **Metal Oxides**: These are generally basic in nature. \(\mathrm{SnO}_2\) and \(\mathrm{PbO}_2\) fall into this category and have applications in ceramics and batteries.
• **Non-Metal Oxides**: Often acidic or neutral, these include \(\mathrm{SiO}_2\), notable for its usage in glass and electronics.

The properties of these oxides are crucial for determining their role in chemical reactions, material science, and environmental science. For instance, their reactivity and stability influence their industrial applications.

Chemical Composition

Exploring the chemical composition of compounds involves looking at the types and ratios of atoms that form them. For oxides, this composition is typically represented by the general formula \(XO_n\), where \(X\) is the element bonded to oxygen. Taking \(\mathrm{SnO}_2\), \(\mathrm{PbO}_2\), and \(\mathrm{SiO}_2\) as examples:

• They feature a fixed ratio of oxygen to the other element (tin, lead, and silicon, respectively).
• This definite proportion is vital for characterizing the specific physical and chemical properties of each compound.

Understanding chemical composition allows chemists to predict reactions and tailor compounds for specific uses. It provides insight into the molecular structure and potential energetic interactions of the elements involved.