Problem 55 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

The option(s) with only amphoteric oxides is(are) (a) \(\mathrm{Cr}_{2} \mathrm{O}_{3}, \mathrm{BeO}, \mathrm{SnO}, \mathrm{SnO}_{2}\) (b) \(\mathrm{Cr}_{2} \mathrm{O}_{3}, \mathrm{CrO}, \mathrm{SnO}, \mathrm{PbO}\) (c) \(\mathrm{NO}, \mathrm{B}_{2} \mathrm{O}_{3}, \mathrm{PbO}, \mathrm{SnO}_{2}\) (d) \(\mathrm{ZnO}, \mathrm{Al}_{2} \mathrm{O}_{3}, \mathrm{PbO}, \mathrm{PbO}_{2}\)

Step-by-Step Solution

Answer

The option with only amphoteric oxides is (a).

Step 1: Understand Amphoteric Oxides

An amphoteric oxide is an oxide that can react with both acids and bases to produce salts and water. Common examples include oxides of metals such as Zinc (ZnO) and Aluminum (Al₂O₃). Identify which of the listed substances are known for amphoteric properties.

Step 2: Analyze Option (a)

The compounds in option (a) are Cr₂O₃, BeO, SnO, and SnO₂. Cr₂O₃, SnO, and SnO₂ are amphoteric. However, BeO can also exhibit amphoteric behavior. Therefore, consider that all oxides here are amphoteric.

Step 3: Analyze Option (b)

The compounds in option (b) are Cr₂O₃, CrO, SnO, and PbO. Cr₂O₃, SnO, and PbO are amphoteric. However, CrO is not amphoteric as it primarily exists as a basic oxide. Thus, not all oxides here meet amphoteric criteria.

Step 4: Analyze Option (c)

The compounds in option (c) are NO, B₂O₃, PbO, and SnO₂. NO is a neutral oxide, and B₂O₃ is an acidic oxide. Thus, this option does not contain only amphoteric oxides as it includes other types of oxides as well.

Step 5: Analyze Option (d)

The compounds in option (d) are ZnO, Al₂O₃, PbO, and PbO₂. ZnO, Al₂O₃, and PbO are amphoteric. However, PbO₂ tends to show more acidic behavior, thus not fulfilling the requirement for all compounds to be amphoteric.

Step 6: Determine the Correct Option

By analyzing each option, option (a) contains only amphoteric oxides. Option (b), (c), and (d) include other types of oxides that are not strictly amphoteric.

Key Concepts

Oxide Properties

Oxides are chemical compounds containing oxygen and another element. They can exhibit different behaviors based on their chemical composition and structure. One of the most intriguing groups is amphoteric oxides, which possess a dual nature. They can react with both acids and bases.
This dual reaction potential makes them unique in the study of oxide properties. Common amphoteric oxides include aluminum oxide \(\mathrm{Al_2O_3}\) and zinc oxide \(\mathrm{ZnO}\).

• Amphoteric oxides react with acids to form water and salts.
• They also react with bases, producing similar products.

Understanding these properties is essential for predicting how these compounds will behave in various chemical environments.

Acid-Base Reactions

Acid-base reactions are fundamental to understanding amphoteric oxides. These oxides have the capability to engage in reactions with both acidic and basic reactants.

• In acidic reactions, amphoteric oxides act as a base. For instance, \(\mathrm{ZnO}\) reacts with hydrochloric acid \(\mathrm{HCl}\) to form \(\mathrm{ZnCl_2}\) and water.
• Conversely, in basic reactions, they behave as an acid. An example is \(\mathrm{Al_2O_3}\) reacting with sodium hydroxide \(\mathrm{NaOH}\) to produce sodium aluminate.

These reactions illustrate the flexible nature of amphoteric oxides. Their dual-reactivity allows them to be used in various industrial and chemical processes. By recognizing these patterns, students can better anticipate the outcomes of chemical reactions involving these oxides.

Inorganic Chemistry

Inorganic chemistry deals with the study of inorganic compounds, including oxides. Amphoteric oxides form a crucial part of this study due to their ability to interact with both acids and bases.
Within the field, these oxides can demonstrate the complex interplay of elements and compounds. Recognizing and understanding their behavior is paramount.

• Amphoteric oxides, such as \(\mathrm{Al_2O_3}\) and \(\mathrm{ZnO}\), highlight the interactions between metals and oxygen. This relationship showcases the chemical versatility of elements.
• The study of these oxides emphasizes the diversity within oxides, ranging from basic, acidic, to neutral forms.

By appreciating the role of amphoteric oxides in inorganic chemistry, students can gain a deeper insight into the fundamental principles governing chemical reactions and compound formation.