• Question: What will happen if idone and benedict's solution mix together ??

    Asked by Hanna to Colin, John, Kevin, Shikha, Triona on 16 Nov 2014.
    • Photo: Shikha Sharma

      Shikha Sharma answered on 16 Nov 2014:

      Hi Hanna,
      To be honest I have no clue what will happen if we add these two solutions. Let me try with the chemistry concepts I remember…Benedict’s reagent is a solution of copper sulfate, sodium carbonate and sodium citrate in water.

      Now when you add copper salts in aqueous solution it dissociates and the metal ions are complexed by the water molecules:
      Cu2+ + 6H2O(l) [Cu(H2O)6]2+(aq)

      Now if you have asked us to add potassium iodide in it. This is a redox reaction with the copper(II) complex being reduced to copper(I) while the iodide ions get oxidized to iodine. The color change from a blue solution to a white suspension of copper(I) sulfate mixed with the brownish iodine.
      2Cu2+ + 2I- 2Cu+ + I2

      But iodine solution it hardly dissolves in water. So, the mixture is going to have iodine, copper sulfate and other two chemicals ….Oops I tried to reach to an answer but its kind of difficult….
      Just one suggestion never try to mix random solution in chemistry lab to see what can happen… it can be dangerous as you don’t know what reaction can happen as I don’t know the correct answer for your question 🙂

    • Photo: Kevin Motherway

      Kevin Motherway answered on 19 Nov 2014:

      I know these reagents are used to test for sucrose and starch. I have no clue what happens when you mix them. Talk to your teacher about assessing if it’s safe to do. Take the precautions necessary for health and safety (goggles, fume cupboard etc as appropriate) and try it out! Remember the most important thing in science is to say ” I don’t know”, and try and find out the answer with a bit of help and supervision to manage any risks. Talk to your teacher and report back. I want or know the result!

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