Question

During dialysis

• A. only solvent molecules can diffuse
• B. solvent molecules, ions and colloidal particles can diffuse
• C. all kinds of particles can diffuse through the semipermeable membrane
• D. solvent molecules and ions can diffuse

Answer 1

The Correct Option is D

Dialysis is a process used to remove waste products and excess substances from the blood when the kidneys are not functioning properly. It involves the diffusion of molecules across a semipermeable membrane.

The key to understanding what happens during dialysis is knowing the nature of the semipermeable membrane. This membrane allows certain types of particles or molecules to pass through while preventing others. Here's the analysis:

• Option 1: Only solvent molecules can diffuse
  This is incorrect. While solvent molecules (like water) can diffuse, ions can also pass through the membrane due to their small size and charge.
• Option 2: Solvent molecules, ions, and colloidal particles can diffuse
  This is incorrect. While solvent molecules and ions can diffuse, colloidal particles are typically too large to pass through the semipermeable membrane used in dialysis.
• Option 3: All kinds of particles can diffuse through the semipermeable membrane
  This is incorrect as the membrane restricts the passage of large molecules, such as proteins and colloids, retaining them in the blood.
• Option 4: Solvent molecules and ions can diffuse (Correct Answer)
  This is correct. During dialysis, solvent molecules (like water) and small ions (such as sodium and potassium) can diffuse through the semipermeable membrane.

Thus, in the context of dialysis, the semipermeable membrane selectively allows the passage of small molecules and ions while preventing larger molecules and particulates from crossing.