CBSE 2025, Set 2

Question

**Read the passage and answer:**

The spontaneous flow of the solvent through a semipermeable membrane from a pure solvent to a solution or from a dilute solution to a concentrated solution is called osmosis. Reverse osmosis takes place when the applied external pressure becomes larger than the osmotic pressure.

(a) Define reverse osmosis. Name one semipermeable membrane (SPM) which can be used in the process of reverse osmosis.

Edvaya · Accepted Answer

The correct answer is Subjective. **Reverse Osmosis:** When external pressure **larger than the osmotic pressure** is applied to the solution side of a semipermeable membrane, the direction of flow of solvent is reversed — it moves from the **solution side to the pure solvent side**. This phenomenon is called **reverse osmosis (RO)**. $$	ext{Applied pressure} > \pi_{	ext{osmotic}} \Rightarrow 	ext{Solvent flows: solution} ightarrow 	ext{pure solvent}$$ **Application:** Used for **desalination of sea water** — salt water is forced through a semipermeable membrane, pure water passes through and salt is left behind. **Semipermeable membrane used in RO:** **Cellulose acetate** (or other acceptable examples: polyamide thin-film composite membranes, cellulose nitrate).

Edvaya Target

Edvaya Aspire

Take a Free Mock Test

Target Subjects

Aspire Subjects

Subject Mastery

Chemistry > Physical Chemistry > Solutions

Keep Practicing

Edvaya Target

Current Question

Community Stats

Track Your Progress

Quick Actions

We Value Your Privacy