system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do iodine tablets purify water in a safe way for people to drink?

I know that there are iodine tablets to purify water, but I have no clue how. And how do they work in a way where it doesn't kill us as opposed to other purification techniques like chlorine?
gpt
Iodine, chlorine dioxide and bleach is strong oxidizing agents. If you add them to water they increase the pH and will dissolve the cell walls of any bacteria , parasites and virus. Your cells will be attacked in the same way but while the bacteria in the water is exposed for theirty minutes your cells will only get exposed for a few seconds before the solution gets neutralized by your stomach acid. And you have a lot more cells then there are bacteria in the water and are able to replace your cells. Adding to this you have a layer of dead cells which protects the live cells underneath. All in all you can handle the high pH much better then any bacteria in the water. However you can also dissolve an acid, for example vitamin-c, into the water once the iodine have done its job to neutralize the water again to make it more plesent to drink. The iodine and vitamin-c will react and form a powder that settles at the bottom of the container.