Monday 21 July 2014

Chemistry: How to make iodine

In the UK iodine is unavailable to buy but there are so many things you can use iodine for in chemistry.  So I have put together this post on how you can make your own which makes for a fun and very educational activity at the same time.

This solution is very useful if you want to try Invisible Ink 4 in my post Invisible inks and the iodine clock reaction experiment.

You must be careful with this iodine solution. If you want to dispose of it dilute it with plenty of water and get rid of it down the sink.

To make iodine you will need:
  • Potassium iodide
  • Sodium hydrogen sulphate
  • hydrogen peroxide
  • water
  • A test tube
  • A clean and dry bottle with a secure lid.
Here we go:  How to make iodine developer


Put about 1/4 of teaspoon of potassium iodide and 1/8 of a teaspoon of sodium hydrogen sulphate into a clean dry test tube with 2cm of water. 


Add 10 drops of hydrogen peroxide solution. 

You will see that you have made a yellowy brown solution. 


Add more water until the test tube is half full and then, if you want to keep it, put it in a clean and dry bottle and label very clearly IODINE SOLUTION!  This is super important as  iodine can be dangerous if swallowed.

1 comment:

  1. I managed to buy some Lugol's iodine on Amazon. Not pure iodine solution but it has worked well for vitamin C testing.