Problem 6 - A Complete Resource Book in Chemistry for JEE Main

Question

On igniting \(\mathrm{Fe}_{2} \mathrm{O}_{3}\) at 1673 (a) \(\mathrm{Fe}_{2} \mathrm{O}_{3}\) starts melting (b) \(\mathrm{FeO}\) is formed (c) metallic iron is formed (d) both (b) and (c)

Step-by-Step Solution

Answer

(d) both (b) and (c)

Step 1: Understanding the Reaction

When \( \mathrm{Fe}_{2}\mathrm{O}_{3} \) is subjected to high temperatures, it undergoes a reduction reaction. This is a way to produce metallic iron by reducing iron oxide.

Step 2: Exploring the Products

The reduction of \( \mathrm{Fe}_{2}\mathrm{O}_{3} \) at very high temperatures like 1673 K may lead to the formation of \( \mathrm{FeO} \) as an intermediate and eventually produce metallic iron \( \mathrm{Fe} \).

Step 3: Conclusion based on Options

The question presents four options. Knowing that during high-temperature reduction, metallic iron can indeed form, we conclude that option (c) is possible. The intermediate formation of \( \mathrm{FeO} \) might also happen, pointing towards option (d) — both (b) and (c).

Key Concepts

Reduction Reaction

A reduction reaction is a chemical process where a molecule, atom, or ion gains electrons. This process often involves the removal of oxygen or the addition of hydrogen. In the context of iron oxide reduction, the main focus is the reduction of iron oxide to iron in a controlled manner.

In chemical reactions involving metals, reduction commonly implies the removal of oxygen from metal oxides. When iron(III) oxide (\( \mathrm{Fe}_{2}\mathrm{O}_{3} \)) is heated, it undergoes a reduction reaction to form iron (Fe). Here, oxygen is released, leaving behind pure metallic iron and sometimes intermediate products. Understanding these reactions is crucial for industries that rely on large-scale metal extraction.

Key concepts to remember about reduction reactions:

• The reducing agent is the substance that donates electrons and gets oxidized.
• The oxidizing agent gets reduced by accepting electrons.
• In the case of iron oxide reduction, oxygen is removed to form metallic iron.

High Temperature Reaction

High temperature reactions are reactions that occur at elevated temperatures, often necessary to facilitate or speed up the reaction process. The energy supplied by high heat can break strong bonds in reactants, allowing new products to form.

When we consider the reaction of \( \mathrm{Fe}_{2}\mathrm{O}_{3} \) at 1673 K, the involvement of high temperatures is crucial. This specific temperature is high enough to break the strong bonds in iron oxide, allowing reduction to take place effectively. At these temperatures, the kinetic energy of particles increases, which can lead to faster reactions and the formation of intermediate products like \( \mathrm{FeO} \). In industrial settings, maintaining the right temperature is key to efficiently obtaining the desired outcome.

Important points about high temperature reactions:

• They provide the necessary energy to break strong atomic bonds.
• Higher temperatures increase the rate of reaction due to increased molecular motion.
• Careful control of temperature is essential to avoid undesired side reactions.

Metallic Iron Production

Metallic iron production is a crucial industrial process that involves the extraction of pure iron from its oxide ores. Usually, iron is extracted in blast furnaces by reducing iron oxides like \( \mathrm{Fe}_{2}\mathrm{O}_{3} \) using a reducing agent, often in the form of coke or another carbon source.

During the reduction of \( \mathrm{Fe}_{2}\mathrm{O}_{3} \) at high temperatures, the oxygen in the oxide is removed, leaving behind metallic iron, sometimes seen first in its intermediate form \( \mathrm{FeO} \), and eventually the pure elemental iron. This process is fundamental to the steel manufacturing industry because iron is a primary component of steel.

Key aspects of metallic iron production:

• The process largely relies on the reduction of iron oxide ores.
• High temperatures accelerate the reaction, leading to efficient extraction of iron.
• Understanding the chemistry behind reduction is key for optimizing iron production in industrial applications.