[Spectrallearner]

We recently did a lab with color changes of certain substances and I was wondering what are the explanations behind them as I just cant figure it out. The results are as shown:

Add acidified potassium iodide          - color change from from dark brown to purple
to acidified potassium manganate

Add hydrogen peroxide to             - colorless
acidified potassium manganate

Add acidified potassium iodide to    - color change of orange to brick red
acidified potassium dichromate

Add acidified potassium iodide         - color change from colorless to yellow  finally to orange
to acidified potassium dichromate

Add acidified potassium dichromate  - color change from colorless to black to green
to hydrogen peroxide

[Hunter2]

We recently did a lab with color changes of certain substances and I was wondering what are the explanations behind them as I just cant figure it out. The results are as shown:

Add acidified potassium iodide          - color change from from dark brown to purple
to acidified potassium manganate

Add hydrogen peroxide to             - colorless
acidified potassium manganate

Add acidified potassium iodide to    - color change of orange to brick red
acidified potassium dichromate

Add acidified potassium iodide         - color change from colorless to yellow  finally to orange
to acidified potassium dichromate

Add acidified potassium dichromate  - color change from colorless to black to green
to hydrogen peroxide

First one will turn in opposite violet to brown.

Add acidified potassium iodide         - color change from colorless to yellow  finally to orange
to acidified potassium dichromate
This can not be.

Check the colours of each compound and the reaction products.

[Spectrallearner]

Wait how can that not be thats what happened?

[Arkcon]

Well, first, you should check what Hunter2: told you to check -- if you're mixing a brown liquid with a purple liquid and get a purple liquid as a result, then you have a reason to know why that result has happened.  You'll have to know the nature of you reagents -- why has something become colorless, then acquired another color?

You may have entered this question the wrong way around.  You say you need to know the reason behind the color changes, when you really need to understand the reactions that are happening to each chemical.