What else turns iodine blue black?

  • Thread starter crays
  • Start date
In summary, the conversation discusses the use of iodine to test for the presence of antioxidants in water. The participants question the validity of a demonstration by a health company claiming to sell alkaline water as an antioxidant. It is stated that the iodine used in the experiment should turn colorless in the presence of an antioxidant, leading to skepticism about the company's claims. The conversation also touches on the use of iodine as an oxidizing agent and the potential for "snake oil" products in the health industry.
  • #1
crays
160
0
Hello guys, i would like to ask, except for starch or carbohydrates, what else could turn iodine blue black in color?
 
Physics news on Phys.org
  • #2
toilet paper??
 
  • #3
Mostly cellulose, so it qualifies as carbohydrates.
 
  • #4
Thank you. Well because there is this health company that says they are selling alkaline water which is an antioxidant. They demonstrated an experiment which they used iodine and with their water, the iodine turned blue black and not colorless so i suspected and asked. thanks.
 
  • #5
I can be missing something, but it doesn't make sense to me.

What do you mean by iodine? Elemental? Or iodine tincture?

But it doesn't matter (much). In both cases you have some amount of iodine - I2 - in the solution. That should be by itself slightly bluish/violet (with depth of the color depending on the concetration and solvent used). If you add any "antioxidant" I would expect it to reduce oxidizing agents, in this case turn iodine (colorful) into iodide (colorless). So something doesn't sound right.

Honestly, when I hear

health company that says they are selling alkaline water which is an antioxidant

I expect snake oil.
 
  • #6
Yeah that is what i learned too. It should turn colorless. Thanks for the info will search it up.
 

1. What is iodine's reaction with starch that causes it to turn blue black?

Iodine has a strong affinity for starch molecules, which are long chains of glucose molecules. When iodine comes into contact with starch, it forms a complex with the glucose chains, resulting in a blue black color.

2. Can anything else besides starch cause iodine to turn blue black?

Yes, some other substances that can cause iodine to turn blue black include glycogen, cellulose, and dextrin. These substances also have glucose molecules, which can form complexes with iodine.

3. Are there any other factors that can affect the color change of iodine and starch?

Yes, the concentration of iodine and starch can affect the intensity of the blue black color. Temperature can also have an impact, as the reaction between iodine and starch is more rapid at higher temperatures.

4. Why is the blue black color only seen in the presence of starch and iodine?

This specific color change is due to the formation of a complex between iodine and starch. This complex absorbs certain wavelengths of light, resulting in the blue black color. Other substances may also form complexes with iodine, but they may result in different colors.

5. Is the reaction between iodine and starch reversible?

Yes, the reaction between iodine and starch is reversible. If the iodine is removed, the blue black color will disappear. This can be achieved by adding a reducing agent, such as vitamin C, which breaks apart the complex between iodine and starch.

Similar threads

  • Biology and Chemistry Homework Help
Replies
3
Views
3K
  • Mechanical Engineering
Replies
10
Views
686
  • Biology and Chemistry Homework Help
Replies
1
Views
4K
  • Precalculus Mathematics Homework Help
Replies
12
Views
1K
Replies
3
Views
2K
  • Mechanics
Replies
6
Views
909
  • Biology and Chemistry Homework Help
Replies
4
Views
4K
Replies
6
Views
1K
  • Introductory Physics Homework Help
Replies
9
Views
129
  • Chemistry
Replies
22
Views
543
Back
Top