Multiple Choice
When testing osmosis using a thistle tube filled with a sucrose solution and placed in pure water, what observation would indicate that osmosis is occurring?
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6. The Membrane
Osmosis
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If a selectively permeable tube containing starch solution is placed in a beaker of iodine solution, and the tube is permeable to iodine but not to starch, what will most likely happen after some time?
A
The color of the starch solution inside the tube will remain unchanged.
B
Starch will diffuse out of the tube into the beaker.
C
Iodine will move into the tube and turn the starch solution blue-black.
D
Iodine will not move into the tube because the membrane is impermeable to it.
Verified step by step guidance1
Understand the concept of selective permeability: A selectively permeable membrane allows certain substances to pass through while blocking others. In this case, the tube is permeable to iodine but not to starch.
Recall the chemical reaction between iodine and starch: When iodine comes into contact with starch, it forms a blue-black complex. This is a key observation in this problem.
Analyze the movement of molecules: Since the tube is permeable to iodine, iodine molecules will diffuse from the beaker into the tube, moving down their concentration gradient.
Consider the impermeability to starch: Starch molecules inside the tube cannot diffuse out into the beaker because the membrane is not permeable to starch.
Predict the outcome: As iodine enters the tube and interacts with the starch solution, the starch solution will turn blue-black due to the chemical reaction between iodine and starch.
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