Problem 146 - A Complete Resource Book in Chemistry for JEE Main

Question

Which is correctly matched? (a) Erionite \(\mathrm{Na}_{2} \mathrm{~K}_{2} \mathrm{CaMg}\left(\mathrm{AlO}_{2}\right)_{2}\left(\mathrm{SiO}_{2}\right)_{2} \cdot 6 \mathrm{H}_{2} \mathrm{O}\) (b) Anionic surfactant \(-\mathrm{C}_{17} \mathrm{H}_{35} \mathrm{COONa}\) (c) Cationic surfactant - (d) None of these

Step-by-Step Solution

Answer

(b) is correctly matched as an anionic surfactant.

Step 1: Understanding the Question

We are asked to determine which option (a), (b), (c), or (d) is correctly matched with its description. Each option represents a different chemical compound or concept.

Step 2: Analyzing Option (a)

Option (a) refers to Erionite, a type of zeolite mineral. The chemical formula provided is incorrect for Erionite. Erionite's formula is usually portrayed as \((Na_2,K_2,Ca)_2Al_4Si_{14}O_{36} \cdot 15H_2O\), and does not match the formula listed here.

Step 3: Examining Option (b)

Option (b) mentions an anionic surfactant \(-C_{17}H_{35}COONa\), which is Sodium stearate, a commonly used anionic surfactant. Surfactants often have a hydrophobic tail and a hydrophilic head, and sodium stearate fits this profile.

Step 4: Reviewing Option (c)

Option (c) states 'Cationic surfactant -' but provides no formula or compound to evaluate. Without information, we cannot ascertain whether any cationic surfactant is correctly matched.

Step 5: Confirming Option (d)

Option (d) states "None of these." However, upon investigation, option (b) is correctly matched as the given formula describes an anionic surfactant.

Step 6: Concluding the Question

Since option (b) correctly matches an anionic surfactant with Sodium stearate, option (d) which states "None of these," is incorrect. Therefore, option (b) is the correct answer.

Key Concepts

Zeolites

Zeolites are a fascinating group of minerals known primarily for their unique porous structure. These minerals are made up of aluminosilicates, meaning they contain aluminum, silicon, and oxygen atoms. What sets zeolites apart is their ability to exchange cations, or positively charged ions, without altering their structure. This property makes them incredibly useful in a variety of applications. Zeolites are often used in water purification, as they can easily trap unwanted ions and impurities. This makes them ideal for ion exchange processes. Additionally, zeolites find use in the petrochemical industry as catalysts. Their porous structure allows them to facilitate chemical reactions by providing a good surface for reactants to interact. It's important to note that zeolites occur naturally but can also be synthesized for specific industrial applications. Their ability to selectively absorb substances based on size makes them invaluable in separation processes. Overall, zeolites function much like molecular sieves, allowing certain molecules to pass while blocking others.

Surfactants

Surfactants, or surface-active agents, are compounds that lower the surface tension between two substances, such as a liquid and a gas or between two liquids. This unique ability makes surfactants extremely useful in various products and industries. One of the primary roles of surfactants is in detergents. They enable water to mix with oil and grease, allowing these substances to be washed away. Surfactants are divided into different categories based on the charge of their head group:

• Anionic surfactants have negatively charged head groups. They are commonly found in soaps and detergents, like sodium stearate.


• Cationic surfactants have positively charged head groups and are often used as fabric softeners and hair conditioners because they can adhere to negatively charged surfaces.


• Nonionic surfactants have no charge and are often used in food and cosmetics because they are less likely to irritate the skin.


• Zwitterionic surfactants contain both positive and negative charges, making them effective in varied environments.

The choice of using a particular type of surfactant depends on the specific application and desired properties.

Chemical Formulas

Chemical formulas are a shorthand way of expressing the elements and their quantities within a compound. Understanding these formulas is crucial for anyone studying or working in chemistry because they convey important information about the chemical composition and structure of substances. There are different types of chemical formulas, including:

• Empirical Formulas, which provide the simplest whole-number ratio of the elements in a compound. For example, the empirical formula for glucose is CH₂O.
• Molecular Formulas, which denote the exact number of each type of atom in a molecule. Using glucose again, its molecular formula is C₆H₁₂O₆.
• Structural Formulas, which illustrate the arrangement of atoms within the molecule, offering insight into the molecular geometry and chemical bonding.

The correct interpretation of these formulas is key to understanding chemical properties and reactions, and even small changes in a formula can significantly alter the characteristics of the compound it represents. Accurate and consistent usage of chemical formulas is essential for clear communication in the scientific community.