An aqueous mixture containing starch (a colloid), NaCl, glucose, and albumin (a colloid) is placed in a dialyzing bag and immersed in distilled water. Which of the following correctly describes the location of the indicated substance after dialysis?
A-albumin, inside
B-starch outside
C-albumin inside and outside
D-water inside only
E-starch inside and outside
To determine the answer, we need to understand the process of dialysis and the behavior of the substances involved.
Dialysis is a process that separates substances based on their size and charge using a semi-permeable membrane. In this scenario, the dialyzing bag acts as the membrane, allowing the passage of small molecules, ions, and water while restricting larger molecules like colloids.
Given that albumin and starch are both colloids and are larger in size, they will be restricted from passing through the dialyzing bag. On the other hand, NaCl and glucose are smaller molecules and can pass through the membrane.
When the mixture is placed in the dialyzing bag and immersed in distilled water, we can expect the following to happen:
- Albumin (a colloid): As a larger molecule, albumin will remain inside the dialyzing bag. It will not be able to pass through the semi-permeable membrane, so it will stay inside the bag. Hence, option A ("albumin, inside") is the correct answer.
- Starch (a colloid): Just like albumin, starch is also a larger molecule and cannot pass through the dialyzing bag's membrane. Therefore, it will stay outside the bag. Thus, option E ("starch inside and outside") is incorrect.
- NaCl and glucose: Both NaCl and glucose are smaller molecules, which means they can pass through the dialyzing bag's membrane. When the bag is immersed in distilled water, these small molecules will be able to diffuse into the water. Consequently, some NaCl and glucose will be found both inside and outside the dialyzing bag. Thus, option C ("albumin inside and outside") is incorrect, and option D ("water inside only") is also incorrect.
In conclusion, the correct answer is option A: "albumin, inside."