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Topic: Reactive to Water Particles  (Read 5207 times)

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Zededin

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Reactive to Water Particles
« on: May 20, 2004, 11:28:24 PM »
I am looking for a compound that is most reactive (and preferably changes color) when exposed to even minute amount of water particles at a particular location on a surface.  I have already tried a Cobalt Chromium paper that changes from pink to blue when the humidity in the air is increased.  However, the sensitivity of the paper that I could acquire is low and changes in color takes a long time.  Thank you in advance.

Offline Donaldson Tan

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Re:Reactive to Water Particles
« Reply #1 on: May 22, 2004, 01:35:56 AM »
Perhaps adding transition metal salts to the hygroscopic NaOH pellets might yield something interesting. NaOH helps to absorb moisture, the transition metal ion changes colour in the presence of water.. It's just a conjecture, but why not? I think there's no harm making a suggestion

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Offline AWK

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Re:Reactive to Water Particles
« Reply #2 on: May 22, 2004, 04:18:43 AM »
Perhaps adding transition metal salts to the hygroscopic NaOH pellets might yield something interesting

But all color cations form hydroxides insoluble in water.
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Offline Donaldson Tan

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Re:Reactive to Water Particles
« Reply #3 on: May 22, 2004, 04:30:36 AM »
Is there any known hygroscopic transition metal compounds that may do the trick, other than Cobalt?
"Say you're in a [chemical] plant and there's a snake on the floor. What are you going to do? Call a consultant? Get a meeting together to talk about which color is the snake? Employees should do one thing: walk over there and you step on the friggin� snake." - Jean-Pierre Garnier, CEO of Glaxosmithkline, June 2006

Offline hmx9123

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Re:Reactive to Water Particles
« Reply #4 on: May 26, 2004, 10:14:30 PM »
There's a good number of inorganic compounds that change color (and usually catch on fire) when exposed to even small amounts of water.  Problem is, they're usually pryophoric as well.  I'm guessing that's not what you're looking for.

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