Question

which of the following is true about the rate of diffusion through a selectively permeable membrane?

the size of the molecules has no effect on the rate of diffusion through the membrane.

smaller molecules diffuse faster than larger molecules through a membrane.

larger molecules diffuse faster than smaller molecules through a membrane.

all molecules diffuse at the same rate through the membrane.

Explanation:

To determine the correct statement about the rate of diffusion through a selectively permeable membrane, we analyze each option:

• The first option is incorrect because the size of molecules does affect diffusion rate (e.g., through membrane pores).
• The second option is correct. Smaller molecules can pass through membrane pores or spaces more easily and quickly than larger molecules, so they diffuse faster.
• The third option is incorrect. Larger molecules have more difficulty moving through the membrane's selective pathways, so they diffuse slower than smaller ones.
• The fourth option is incorrect. Different - sized molecules have different diffusion rates due to the selective permeability of the membrane (e.g., based on size, charge, etc.).

Answer:

B. Smaller molecules diffuse faster than larger molecules through a membrane.