Problem 133 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the following: List-I List-II 1\. Beryl (i) \(\mathrm{KCl} \cdot \mathrm{MgCl}_{2} .6 \mathrm{H}_{2} \mathrm{O}\) 2\. Carnalite (ii) \(\mathrm{MgCO}_{3}\) 3\. Asbestos (iii) \(3 \mathrm{BeO} \cdot \mathrm{Al}_{2} \mathrm{O}_{3} \cdot 6 \mathrm{SiO}_{2}\) 4\. Magnesite (iv) \(\mathrm{Ca}_{2} \mathrm{Mg}_{5} \mathrm{Si}_{8} \mathrm{O}_{22}(\mathrm{OH})_{2}\) (v) \(\mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O}\) The correct matching is: 1 \(\begin{array}{lll}2 & 3 & 4\end{array}\) (a) (iii) (iv) (i) (ii) (b) (iv) (iii) (ii) (i) (c) (iii) (i) (iv) (ii) (d) (iii) (i) (ii) (iv)

Step-by-Step Solution

Answer

The correct matching is option (c): 1-(iii), 2-(i), 3-(iv), 4-(ii).

Step 1: Understand the Problem

We are given a matching problem where we have to match items from List-I with the correct items from List-II. Each item on List-I is a mineral or chemical compound, and we need to identify its correct chemical formula or composition from List-II.

Step 2: Analyze List-I

List-I consists of minerals: 1. Beryl 2. Carnalite 3. Asbestos 4. Magnesite We need to match them with their corresponding chemical formulas or compositions.

Step 3: Analyze List-II

List-II consists of chemical formulas:(i) \( \mathrm{KCl} \cdot \mathrm{MgCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O} \)(ii) \( \mathrm{MgCO}_{3} \)(iii) \( 3 \mathrm{BeO} \cdot \mathrm{Al}_{2} \mathrm{O}_{3} \cdot 6 \mathrm{SiO}_{2} \)(iv) \( \mathrm{Ca}_{2} \mathrm{Mg}_{5} \mathrm{Si}_{8} \mathrm{O}_{22}(\mathrm{OH})_{2} \)(v) \( \mathrm{CaSO}_{4} \cdot 2 \mathrm{H}_{2} \mathrm{O} \)

Step 4: Match Beryl

Beryl is known to have the formula \( 3 \mathrm{BeO} \cdot \mathrm{Al}_{2} \mathrm{O}_{3} \cdot 6 \mathrm{SiO}_{2} \). Thus, Beryl matches with (iii).

Step 5: Match Carnalite

Carnalite is known to have the formula \( \mathrm{KCl} \cdot \mathrm{MgCl}_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O} \). Thus, Carnalite matches with (i).

Step 6: Match Asbestos

Asbestos is known to have the complex silicate formula \( \mathrm{Ca}_{2} \mathrm{Mg}_{5} \mathrm{Si}_{8} \mathrm{O}_{22}(\mathrm{OH})_{2} \). Thus, Asbestos matches with (iv).

Step 7: Match Magnesite

Magnesite is composed of \( \mathrm{MgCO}_{3} \). Thus, Magnesite matches with (ii).

Step 8: Compose the Correct Matching Order

Using the matches found, arrange them in order: 1. Beryl - (iii) 2. Carnalite - (i) 3. Asbestos - (iv) 4. Magnesite - (ii) This arrangement corresponds to option (c) from the given choices.

Key Concepts

Beryl

Beryl is a fascinating mineral that often presents itself in captivating shades of green and blue. Its chemical formula is quite unique: \(3 \text{BeO} \cdot \text{Al}_2 \text{O}_3 \cdot 6 \text{SiO}_2\). This formula reveals its structure containing beryllium, aluminum, and silicon dioxide.

Beryl is best known for its gem-quality varieties, such as emerald and aquamarine, which belong to the same mineral family. It is a crystal that forms hexagonal structures and can incorporate a variety of elements, which influences its color.

In its geological environment, beryl can be found in granitic pegmatites and mica schists. Beyond being a gemstone, beryl and its derivatives are essential since they serve as an important source of the metal beryllium, widely used in aerospace and other high-tech industries.

Carnalite

Carnalite is a mineral with the chemical formula \( \text{KCl} \cdot \text{MgCl}_2 \cdot 6 \text{H}_2 \text{O}\). It is classified as an evaporite mineral, found in sedimentary environments where bodies of water evaporate and leave behind layers of salts.

This mineral is significant in the mining of potassium and magnesium, key elements used in fertilizers and numerous industrial applications. Due to its solubility, it typically manifests in colorful, fibrous masses crystalized in various shades, including pink and yellow.

Carnalite not only serves as an important raw material in agriculture but also contributes to the production of diverse items, from glass to other chemical compounds. Its role in agriculture, specifically in fertilizers, helps increase crop yields by improving soil nutrient content.

Asbestos

Asbestos is a group of silicate minerals known for their fibrous structure and heat resistance. Specifically, the formula \( \text{Ca}_2 \text{Mg}_5 \text{Si}_8 \text{O}_{22}(\text{OH})_2 \) represents one of its common forms.

These minerals have been widely used in various industries for products needing durability against heat and chemical damage, such as insulation materials. However, asbestos is infamous for its health risks: inhalation of its fine fibers can lead to respiratory issues, including asbestosis and cancer.

As a result, many countries have strict regulations on the use of asbestos-containing products. Despite the health risks, the study and management of asbestos are vital due to its presence in older buildings and industrial sites. Understanding how to safely handle and remove asbestos remains an essential aspect of contemporary environmental health practices.

Magnesite

Magnesite, with the chemical formula \(\text{MgCO}_3\), is a mineral primarily composed of magnesium carbonate. It's typically found in sedimentary rocks and forms via the alteration of magnesium-rich rocks through chemical weathering.

Recognizable by its varying colors, often white or gray, it may also have tints of yellow or brown depending on mineral impurities. Magnesite serves an essential role in the manufacturing of refractory materials, used to line kilns due to its high melting point.

Additionally, it is important for producing magnesium oxide, used not only in industrial applications but also as a component in agricultural products, helping to balance soil pH levels. Magnesite is also used for creating synthetic magnesia, important in water filtration systems and cement.