Potassium Iodide

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remlap12
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Potassium Iodide

Post by remlap12 » 25 Jun 2020, 12:17

Hi all,

I have a question about the colour of Potassium Iodide.
I have a small amount in a bottle, made up some time ago, that is a strong yellow colour.
I needed to make some up today, it is clear.
The older solution says saturated, the one I made today is 2M.
What colour should it be ???

TIA
Helen.
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remlap12
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Marama T
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Re: Potassium Iodide

Post by Marama T » 25 Jun 2020, 12:51

Hi Helen. I've got saturated KI in the chem store, which is quite yellow, and some 1M, which is clear. So your 2M stuff should probably be clear.

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remlap12
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Re: Potassium Iodide

Post by remlap12 » 25 Jun 2020, 13:29

Thanks Marama T :D
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remlap12
science support and problem solver :mail:

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Anastasia
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Re: Potassium Iodide

Post by Anastasia » 25 Jun 2020, 14:11

Potassium iodide is usually reacted with lead nitrate to give a bright yellow precipitate.
Could it be that your potassium iodide is contaminated?

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Lyn
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Re: Potassium Iodide

Post by Lyn » 25 Jun 2020, 16:24

Potassium iodide of any strength 1M or 2M, will eventually turn yellow in its container, usually pale yellow. That colour change happens after a long period of time. Even my 0.1M solution has a faint hint of colour but it has been sitting on the shelf for a long time. So I may have to make up a fresh batch when it is next required. The saturated solution is a dark yellow right now. Another fresh batch coming up when someone needs it.

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remlap12
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Re: Potassium Iodide

Post by remlap12 » 29 Jun 2020, 09:47

Thanks for the replies, everyone!
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remlap12
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kimmy
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Re: Potassium Iodide

Post by kimmy » 29 Jun 2020, 13:28

maybe it is Iodine (Potassium Iodide)

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