Problem 167 - A Complete Resource Book in Chemistry for JEE Main

Question

Match the follow.ing Column-I (a) Dispersion medium moves in an electric field (b) Solvent molecules pass through semipermeable membrane towards soolvent side (c) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes. (d) Solvent molecules pass through semi permeable membranes Column-II (p) Osmosis (q) Electrophoresis (r) Electroosmosis (s) Reverse Osmosis

Step-by-Step Solution

Answer

(a)-r, (b)-s, (c)-q, (d)-p.

Step 1: Understand the terms in Column-I

Column-I describes different phenomena related to solutions and colloids. We have to match them with their correct descriptions from Column-II. Let's break them down: (a) Dispersion medium moves in an electric field. (b) Solvent molecules pass through a semipermeable membrane towards the solvent side. (c) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes. (d) Solvent molecules pass through semi-permeable membranes.

Step 2: Match each term with its definition

Let's match the terms with the descriptions given in Column-II: - (a) Dispersion medium moves in an electric field: This is called **Electroosmosis** (r), where the movement of the liquid component of a colloid through a membrane is due to an electric field. - (b) Solvent molecules pass through a semipermeable membrane towards the solvent side: This happens in **Reverse Osmosis** (s), where the solvent moves against the concentration gradient often using pressure. - (c) Movement of charged colloidal particles under the influence of applied electric potential towards oppositely charged electrodes: This phenomenon is **Electrophoresis** (q), used to separate particles based on charge. - (d) Solvent molecules pass through semipermeable membranes: This is a classic description of **Osmosis** (p), where solvent naturally moves from low to high solute concentration through a semipermeable membrane.

Key Concepts

Electroosmosis

Electroosmosis is a fascinating phenomenon where the liquid component of a colloid moves through a porous material or membrane under the influence of an electric field. It differs from other similar processes because it's specifically the movement of the dispersion medium (usually the liquid portion) that is driven by electricity. Imagine a sponge filled with a liquid; electroosmosis would be akin to using electricity to pull that liquid out of the sponge.

This process is significant across various fields such as biology and chemistry, where it helps in separating and manipulating substances. It plays a crucial role in applications like microfluidics and soil decontamination. Electroosmosis can be used to control the flow of fluids at a microscale, which is essential in developing modern lab-on-a-chip devices.

• Driven by electric fields
• Affects the dispersion medium
• Widely used in scientific applications

Reverse Osmosis

Reverse osmosis is a critical process, widely used for purifying water. It involves the passage of solvent molecules through a semipermeable membrane, moving from a dilute solution to a more concentrated one. This might sound unusual since it's the opposite of natural osmosis. The process requires an application of external pressure, typically high, to overcome natural osmotic pressure.

This method is utilized in desalination plants and water purification systems. By applying this process, impurities and larger molecules, such as salts and contaminants, can be filtered out, providing clean drinking water.

• Opposite of natural osmosis
• Requires external pressure
• Effective for water purification

Electrophoresis

Electrophoresis is a common method used in laboratories for separating charged particles. When an electric field is applied, particles move towards the electrode bearing the opposite charge. The speed of this movement depends on the size and charge of the particles. Electrophoresis is crucial in molecular biology for analyzing DNA, RNA, and protein samples.

Two main types of electrophoresis are agarose gel electrophoresis and polyacrylamide gel electrophoresis. These are chosen based on the size and nature of the molecules being studied. By applying this technique, scientists can determine the molecular size of DNA fragments, identify specific proteins in a mixture, or study genetic markers used in forensic analysis.

• Moves charged particles
• Crucial in DNA and protein analysis
• Various methods available

Osmosis

Osmosis is a fundamental concept often described as the movement of solvent molecules through a semipermeable membrane from an area of low solute concentration to an area of high solute concentration. This natural process doesn't require energy and is a critical mechanism in biological systems.

Osmosis helps maintain cellular hydration, regulate nutrient absorption, and balance bodily fluids. In plants, it is vital for absorbing water from the soil and maintaining rigidity of tissues. Understanding osmosis is essential in fields like botany, physiology, and medicine.

• Natural and spontaneous process
• Requires a semipermeable membrane
• Integral to biological systems