Problem 49 - A Complete Resource Book in Chemistry for JEE Main

Question

Which of the following is a ferrite? (a) \(\mathrm{MgFe}_{2} \mathrm{O}_{4}\) (b) \(\mathrm{Zn}_{3} \mathrm{FeO}_{4}\) (c) \(\mathrm{AlFe}_{2} \mathrm{O}_{4}\) (d) \(\mathrm{Na}_{2} \mathrm{Fe}_{2} \mathrm{O}_{4}\)

Step-by-Step Solution

Answer

The ferrite is (a) \(\mathrm{MgFe}_2\mathrm{O}_4\).

Step 1: Understanding Ferrites

Ferrites are ceramic compounds consisting of iron oxide and one or more other metallic elements. They typically have the formula \(MFe_2O_4\), where \(M\) is a metal such as magnesium (Mg), zinc (Zn), or other similar metals.

Step 2: Identify the Ferrite Compound

We need to determine which of the given options fits the formula \(MFe_2O_4\). Look closely at each compound provided: 1. \(\mathrm{MgFe}_2\mathrm{O}_4\)2. \(\mathrm{Zn}_3\mathrm{FeO}_4\)3. \(\mathrm{AlFe}_2\mathrm{O}_4\)4. \(\mathrm{Na}_2\mathrm{Fe}_2\mathrm{O}_4\)Only option (a), \(\mathrm{MgFe}_2\mathrm{O}_4\), matches the \(MFe_2O_4\) formula, where \(M\) is magnesium (Mg).

Step 3: Verifying the Structure

To ensure correctness, confirm that the structure of \(\mathrm{MgFe}_2\mathrm{O}_4\) meets the typical characteristics of ferrites. This compound has magnesium as the divalent metal and fits the general ferrite structure \(MFe_2O_4\).

Key Concepts

Ceramic Compounds

Ceramic compounds are materials made by combining metal and non-metal elements. These compounds are known for their robustness and withstand high temperatures, leading to their use in various applications. One of their key features is their crystal structure.

• They are not metallic but can contain metal atoms.
• They are often insulating, making them ideal for electronic applications.
• Their structures give them a high degree of toughness and thermal resistance.

Ceramic compounds are used widely in engineering and technology. Due to their properties, they are essential in the manufacture of insulators, heat-resistant components, and even as materials in spacecraft. This makes them highly valuable in industries where durability and strength are crucial.

Iron Oxide

Iron oxide is a vital element in creating ferrites as well as many other chemical compounds. You might know it by its common form, rust, but it is far more versatile than that simple description. Iron oxides have the following notable characteristics:

• They are often present in a variety of mineral forms.
• They can exhibit magnetic properties, which make them useful in electronic devices.

In the context of ferrites, iron oxide is crucial because it combines with other metals to create the characteristic magnetic properties. This makes them excellent candidates for transformers and inductors in electronic circuits. Ferrites that include iron oxide are essential for these applications because they contribute to reducing electrical losses, thus making systems more efficient.

Chemical Formula

The chemical formula of a compound tells us exactly what elements are present and in what ratios. For ferrites, the formula is typically given as \(MFe_2O_4\), where \(M\) is a metal atom. This formula is a blueprint that represents the structural makeup of the ferrite. Key elements of understanding chemical formulas include:

• The letters represent the elements involved.
• The subscript numbers show the proportion of each element in the compound.

Let's break it down using the example formula mentioned earlier, \(MFe_2O_4\): - \(M\): Represents the metal in the compound, such as magnesium (Mg) or zinc (Zn).- \(Fe_2\): Indicates that there are two iron atoms.- \(O_4\): Indicates that there are four oxygen atoms.This structural formula is not just a theoretical construct but translates directly to how the atoms are bonded and interact with each other, impacting the material's physical and chemical properties.