Problem 68 - A Complete Resource Book in Chemistry for JEE Main

Question

Latex can be coagulated with? (a) \(\mathrm{CH}_{3} \mathrm{COOH}\) (b) \(\mathrm{H}_{2} \mathrm{O}\) (c) \(\mathrm{CH}_{3} \mathrm{OH}\) (d) All of these

Step-by-Step Solution

Answer

(a) \(\mathrm{CH}_{3}\mathrm{COOH}\).

Step 1: Understanding the Problem

The problem asks us which substance can coagulate latex. Coagulation in this context refers to the process by which a liquid rubber mixture is transformed into a solid or semi-solid mass. This often involves the destabilization and aggregation of particles.

Step 2: Evaluating Each Option

Let's consider each option:- Option (a) is \(\mathrm{CH}_{3}\mathrm{COOH}\), which is acetic acid, a well-known coagulating agent for latex.- Option (b) is \(\mathrm{H}_{2}\mathrm{O}\), or water. Water alone does not coagulate latex; it usually requires acidic or basic conditions.- Option (c) is \(\mathrm{CH}_{3}\mathrm{OH}\), or methanol. Methanol can help in the coagulation of latex.Option (d) suggest all of these, however, as per the analysis above, water alone does not coagulate latex.

Step 3: Choosing the Correct Answer

Based on our evaluation:- \(\mathrm{CH}_{3}\mathrm{COOH}\) is a correct coagulating agent.- \(\mathrm{H}_{2}\mathrm{O}\) is not a coagulating agent by itself.- \(\mathrm{CH}_{3}\mathrm{OH}\) can act as a coagulating agent.Thus, the correct answer is (a) \(\mathrm{CH}_{3}\mathrm{COOH}\) because it directly acts in the coagulation process of latex, while (d) is incorrect due to water.

Key Concepts

Latex Chemistry

Latex chemistry involves the study of natural or synthetic polymers, which are tiny particles suspended in a liquid. In natural rubber latex, these polymers are composed of isoprene units. Latex is essentially a colloidal dispersion, meaning it comprises solid particles dispersed in a liquid.
Latex is notable for its remarkable elasticity and resilience. These properties make it essential in various applications like gloves or balloons. In latex chemistry, understanding the balance between stability and coagulation of these colloidal particles is crucial.

• **Natural latex** is obtained from the sap of rubber trees, where it is stabilized in its native form.
• **Synthetic latex**, on the other hand, is produced through polymerization processes, creating materials like styrene-butadiene rubber.

Handling latex involves maintaining the stability of its colloidal state until desired solidification. This is often achieved by controlling its environment, including pH levels and the presence of specific chemical agents.

Coagulation Agents

Coagulation agents are substances that promote the clumping of particles within a colloidal system, leading to its transformation into a gel or solid mass. In the context of latex, specific chemicals can facilitate this process by disrupting the stability of the latex mixture.
Different agents can affect latex in distinct ways based on their chemical properties.

• **Acids**, like acetic acid (\(\mathrm{CH}_3\mathrm{COOH}\)), are commonly used coagulating agents as they lower the pH, destabilizing the latex particles and causing them to coagulate.
• **Alcohols**, such as methanol (\(\mathrm{CH}_3\mathrm{OH}\)), can also help in latex coagulation, typically by dehydrating the system, which encourages the particles to come together.

Choosing the right coagulating agent depends on the specific application and desired properties of the final product. It is important to also consider factors such as the concentration of the agent and the temperature of the system to achieve the best results.

Chemical Reactions in Chemistry

In chemistry, chemical reactions involving latex coagulation are fascinating due to the interplay of various forces and structures. Coagulation involves changing the physical state of latex by provoking aggregation of its particles.
Within the latex system, stabilization is maintained by electric charges on the particles' surfaces. The introduction of chemicals such as acetic acid or methanol alters these charges, leading to coagulation.

• **Acid-induced coagulation**: The acetic acid (\(\mathrm{CH}_3\mathrm{COOH}\)) neutralizes the negative charges, decreasing electrostatic repulsions and promoting particle aggregation.
• **Solvent effects**: Methanol (\(\mathrm{CH}_3\mathrm{OH}\)) acts differently by reducing the dielectric constant of the medium, causing the particles to come together.

The success of coagulation relies heavily on the understanding of how these agents interact chemically and physically with the latex system. These insights are vital for manipulating and optimizing the properties of latex products.