In this experiment, you're dealing with a scenario involving the diffusion of iodine and starch across a semi-permeable membrane (the dialysis tubing).
Here's what happens step by step:
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Iodine's Properties: Iodine is a small molecule that can easily pass through the dialysis tubing. It will diffuse from the inside of the dialysis bag (where there is iodine solution) to the outside (the beaker).
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Starch's Properties: Starch is a large, complex carbohydrate that cannot pass through the dialysis tubing. Therefore, the starch solution will remain in the beaker and will not enter the dialysis bag.
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Color Reaction: When iodine comes into contact with starch, a blue-black color develops due to the formation of a complex between iodine and amylose (a component of starch).
Now, let's analyze the situation:
- Initially, the starch solution in the beaker is clear or colorless because starch does not react with any free iodine present in the solution.
- As iodine diffuses out of the dialysis tubing into the beaker, it will mix with the starch.
- If sufficient iodine enters the beaker to react with the starch, you will observe a color change. The iodine will interact with the starch, resulting in the formation of the blue-black complex.
Given this reasoning, the color of the water in the beaker at the end of the experiment would be blue-black, not orange or brown. The black color results from the starch-Iodine reaction and is due to the presence of both starch and iodine in the solution after diffusion occurs.