Question

Select the correct statements (1) Oxides of boron \(\left(\mathrm{B}_{2} \mathrm{O}_{3}\right)\) and silicon \(\left(\mathrm{SiO}_{2}\right)\) are acidic in nature. (2) Oxides of aluminium \(\left(\mathrm{Al}_{2} \mathrm{O}_{3}\right)\) and gallium \(\left(\mathrm{Ga}_{2} \mathrm{O}_{3}\right)\) are amphoteric in nature. (3) Oxides of germanium \(\left(\mathrm{GeO}_{2}\right)\) and \(\operatorname{tin}\left(\mathrm{SnO}_{2}\right)\) are acidic in nature. (4) both (1) and (2)

Short answer

Statements (1), (2) and (4) are correct.

Step-by-step solution

Understanding acidic oxides

An acidic oxide reacts with water to form an acid. Boron trioxide \(B_2O_3\) and silicon dioxide \(SiO_2\) are examples of such oxides.

Examining oxide nature of boron and silicon

For statement (1), both \(B_2O_3\) and \(SiO_2\) are acidic oxides. Thus, statement (1) is correct.

Understanding amphoteric oxides

An amphoteric oxide can react with both acids and bases to form salts and water. Aluminium oxide \(Al_2O_3\) and gallium oxide \(Ga_2O_3\) exhibit this characteristic.

Examining oxide nature of aluminum and gallium

For statement (2), both \(Al_2O_3\) and \(Ga_2O_3\) are amphoteric oxides. Hence, statement (2) is correct.

Understanding acidic nature of oxides of germanium and tin

For statement (3), germanium oxide \(GeO_2\) is acidic but tin dioxide \(SnO_2\) is amphoteric, not purely acidic.

Combining results

Since statements (1) and (2) are individually correct, statement (4) is also correct.

Key concepts

Acidic Oxides

Acidic oxides are compounds that react with water to produce acids. They are typically formed by the combination of oxygen with non-metals or certain metals in high oxidation states. When dissolved in water, these oxides form acidic solutions. Here are some examples:
Boron trioxide \(\backslash mathrm {B}_{2} \backslash mathrm {O} _{3}\) which forms boric acid in water.
Silicon dioxide \(\backslash mathrm {SiO} _{2}\) which forms silicic acid in water.
Characteristics of Acidic Oxides:

• They provide H⁺ ions when dissolved in water, making the solution acidic.
• They generally react with bases to form salts and water.

Understanding these properties helps in identifying oxides and predicting their behavior in chemical reactions.

Amphoteric Oxides

Amphoteric oxides are unique compounds that can react with both acids and bases. This dual nature allows them to form salts and water with either type of reactant. Examples include:
Aluminium oxide \(\backslash mathrm {Al}_{2} \backslash mathrm {O} _{3}\) which reacts with hydrochloric acid (an acid) to form aluminium chloride and water, and with sodium hydroxide (a base) to form sodium aluminate and water.
Gallium oxide \(\backslash mathrm {Ga}_{2} \backslash mathrm {O} _{3}\) which displays similar behavior.
Characteristics of Amphoteric Oxides:

• They can react with either acids or bases to form salts and water.
• They often include metallic elements like aluminium, zinc, or tin.

Knowing about amphoteric oxides enables better understanding of the complex reactions these compounds can participate in.

IIT JEE Chemistry

The IIT JEE chemistry syllabus covers a vast range of topics, including the properties of oxides. For test preparation, it is crucial to have a clear understanding of different types of oxides such as acidic and amphoteric oxides.
Tackling problems involving oxides:

• Understand the basic definitions and properties of acidic and amphoteric oxides.
• Practice identifying examples of each type of oxide and their reactions with acids and bases.
• Refer to textbook solutions and step-by-step methods to strengthen your concept clarity.

Approaching these topics with a strong foundational knowledge will help students excel in exams like the IIT JEE.