Question

Match the column I with column II and mark the appropriate choice. $$ \begin{array}{|l|l|l|l|} \hline \text { (A) } & \text { Used as lubricant } & \text { (i) } & \begin{array}{l} \text { Carbon } \\ \text { dioxide } \end{array} \\ \hline \text { (B) } & \begin{array}{l} \text { Oxide with three- } \\ \text { dimensional structure } \end{array} & \text { (ii) } & \text { Graphite } \\ \hline \text { (C) } & \text { Used in solar cells } & \text { (iii) } & \text { Silica } \\ \hline \text { (D) } & \begin{array}{l} \text { Anhydride of carbonic } \\ \text { acid } \end{array} & \text { (iv) } & \text { Silicone } \\ \hline \end{array} $$ (a) \((A) \rightarrow(i v),(B) \rightarrow(i i i),(C) \rightarrow(i i),(D) \rightarrow(i)\) (b) (A) \(\rightarrow\) (iv), (B) \(\rightarrow(\mathrm{i}),(\mathrm{C}) \rightarrow\) (iii), (D) \(\rightarrow\) (ii) (c) (A) \(\rightarrow\) (iii), (B) \(\rightarrow\) (ii), (C) \(\rightarrow\) (i), (D) \(\rightarrow\) (iv) (d) \((\mathrm{A}) \rightarrow(\mathrm{ii}),(\mathrm{B}) \rightarrow(\mathrm{iii}),(\mathrm{C}) \rightarrow(\mathrm{iv}),(\mathrm{D}) \rightarrow(\mathrm{i})\)

Short answer

The correct matching is (a): (A) \rightarrow (ii), (B) \rightarrow (iii), (C) \rightarrow (iv), (D) \rightarrow (i).

Step-by-step solution

- Identify Properties

First, identify the well-known properties of each of the substances listed in Column II. Graphite is known to be a lubricant due to its layered structure. Silica, or silicon dioxide, is an oxide with a three-dimensional structure. Silicone is commonly used in solar cells, and carbon dioxide is a gaseous compound that is the anhydride of carbonic acid.

- Match the Properties to the Uses

Match the properties identified in Step 1 to the uses mentioned in Column I. (A) being a lubricant matches with graphite (ii). (B) oxide with a three-dimensional structure corresponds to silica (iii). (C) used in solar cells corresponds to silicone (iv). Lastly, (D) the anhydride of carbonic acid is carbon dioxide (i).

- Choose the Correct Option

Compare the matched pairs from Step 2 with the given options (a), (b), (c), and (d) to find the correct match. (A) is matched with (ii), (B) is matched with (iii), (C) is matched with (iv), and (D) is matched with (i), therefore the correct choice is option (a).

Key concepts

Lubricants in Chemistry

In chemistry, lubricants play a critical role in reducing friction and wear between surfaces in contact with one another. The classic example of a lubricant is graphite, which works effectively due to its unique layered structure. Each layer is composed of carbon atoms bonded in a hexagonal lattice, and the layers are held together by weak van der Waals forces. This allows them to slide over each other easily, making graphite a superb dry lubricant used in various industrial and mechanical applications. This property is pivotal not only in heavy machinery but also in the development of products like pencils, where the graphite core leaves a mark due to its layers shearing off onto paper.

Understanding the structure and function of lubricants helps students grasp their importance in reducing energy loss and minimizing the potential for mechanical failure, an essential focus within tribology — the study of friction, wear, and lubrication.

Oxides and their Structures

Oxides are chemical compounds that contain at least one oxygen atom and one other element in their chemical formula. They can exhibit a variety of structures, from simple molecules like CO₂ to complex, three-dimensional frameworks like that of silica (SiO₂). Silica is one of the most abundant oxides on Earth, forming a substantial part of the earth's crust. Its network structure consists of silicon atoms covalently bonded to four oxygen atoms, forming a tetrahedral shape. This three-dimensional arrangement of silica leads to the formation of quartz and is also integral in various forms of glass and sand. The structural diversity of oxides is vast, impacting a wide array of fields including material science, ceramics, and environmental chemistry.

When students identify the structures of oxides, they can predict and understand the diverse properties and applications of these compounds, from their electrical and thermal insulation characteristics to their hardness and transparency.

Applications of Silicon Compounds

Silicon compounds, particularly silicones, possess a wide array of applications thanks to their chemical and physical properties. Silicone is remarkable for its thermal stability, resistance to oxidation, and water-repellent nature. These polymers are used in medical devices, cookware, sealants, and lubricants. The flexibility and durability of silicones also make them ideal for use in solar panels, where they encapsulate and protect photovoltaic cells from environmental factors without inhibiting their efficiency. Moreover, the semiconductor properties of silicon itself are fundamental to the functioning of electronic devices. As a result, it is vital in the production of computers, smartphones, and solar cells. By exploring the applications of silicon compounds, students can connect the dots between chemistry and cutting-edge technology, linking classroom concepts to real-world innovations.

Anhydride in Chemistry

An anhydride is a chemical compound that contains the functional group -O-O-, which results from the removal of water (H₂O) from an acid. For instance, carbon dioxide (CO₂) is the anhydride formed from carbonic acid (H₂CO₃). When studying anhydrides, it's important to understand that they can react with water to reform the original acid or with alcohols to form esters. Anhydrides can be derived from both inorganic and organic acids and have significant use in the synthesis of various chemicals. They are utilized in the production of dyes, fragrances, and even pharmaceuticals. Appreciating the role of anhydrides helps students see the connection between simple reactions, such as dehydration, and complex industrial processes that deliver a myriad of products essential for modern life.

Connecting the theoretical aspects of anhydrides with their practical uses supports an integrative learning experience, furthering the students' comprehensive understanding of chemical reactions and their industrial significance.