Question

Arrange the following based on the particle size that are separated out from a solution.
A. Ultrafiltration
B. Sedimentation
C. Filter paper (Whatman 40)
D. Press filtration
Choose the correct answer from the options given below:

• A. B, D, C, A
• B. C, B, A, D
• C. B, A, C, D
• D. A, B, C, D

Hint:

Think of the separation "intensity." Gravity (Sedimentation) only works for big, heavy stuff. You need specialized, tight membranes (Ultrafiltration) to catch the "invisible" tiny particles!

Answer 1

The Correct Option is A

Concept: Separation processes are categorized by the size of the particles they can effectively remove from a fluid. This ranges from large bulk solids to microscopic macromolecules.

Step 1: Analyze the particle size limits for each method.

• B. Sedimentation: Relies on gravity to settle out the largest particles, typically $>100~\mu m$.
• D. Press filtration: Uses mechanical pressure to force fluid through a medium; typically handles coarse to medium solids in the $10$ to $100~\mu m$ range.
• C. Filter paper (Whatman 40): A standard laboratory grade for medium-fine crystalline precipitates, with a particle retention of approximately $8~\mu m$.
• A. Ultrafiltration: A membrane process capable of separating extremely small particles, including macromolecules and viruses, in the $0.001$ to $0.1~\mu m$ range.

Step 2: Arrange from largest to smallest particle size.
The sequence of decreasing particle size removed is: Sedimentation (B) $>$ Press filtration (D) $>$ Filter paper (C) $>$ Ultrafiltration (A).