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Topic: tollens silver mirror - and the dangers of it  (Read 14404 times)

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Offline bottleneckfun

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tollens silver mirror - and the dangers of it
« on: June 01, 2012, 02:44:05 AM »
I thought it would be fun to do a Tollens test with the fairly common ingredients of sodium hydroxide, silver nitrate, ammonia, and sugar.  I mixed everything in that order in a glass tube, capped it, and have let it set.  It made a nice mirror after awhile.  The solution is still in the tube and it is still capped.

However, I have since found out that it can make side reactions that can explode.  This is making me nervous.  Should I be concerned?  How should I treat the tube and reagents to make it safe?  Can I just pore them down the bathroom sink?

Offline discodermolide

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Re: tollens silver mirror - and the dangers of it
« Reply #1 on: June 01, 2012, 03:02:02 AM »
I thought it would be fun to do a Tollens test with the fairly common ingredients of sodium hydroxide, silver nitrate, ammonia, and sugar.  I mixed everything in that order in a glass tube, capped it, and have let it set.  It made a nice mirror after awhile.  The solution is still in the tube and it is still capped.

However, I have since found out that it can make side reactions that can explode.  This is making me nervous.  Should I be concerned?  How should I treat the tube and reagents to make it safe?  Can I just pore them down the bathroom sink?

What scale did you do it on. If it was test tube size I don't think you should be worried about explosions.
I would not put it down the sink. Adsorb it onto some soil or sand and place the resulting material in a bag and place in the trash. Then the whole lot will be incinerated.
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Offline bottleneckfun

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Re: tollens silver mirror - and the dangers of it
« Reply #2 on: June 01, 2012, 05:05:38 AM »
Yes, it is in a test tube with a cork.  By not worrying about explosions, do you mean (1) that it is unlikely to explode, so I could bet money that it won't; (2) that it will definitely not explode, so I could bet my life that it won't; (3) that it won't even heat up, so I could put the tube in a barrel of gasoline and sleep on top of it; or (4) something else?

Should test tube and all be mixed with soil and placed in the trash, or just the liquid inside?  After that, is the silver-mirrored tube completely safe?

Offline discodermolide

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Re: tollens silver mirror - and the dangers of it
« Reply #3 on: June 01, 2012, 06:55:52 AM »
Yes, it is in a test tube with a cork.  By not worrying about explosions, do you mean (1) that it is unlikely to explode, so I could bet money that it won't; (2) that it will definitely not explode, so I could bet my life that it won't; (3) that it won't even heat up, so I could put the tube in a barrel of gasoline and sleep on top of it; or (4) something else?

Should test tube and all be mixed with soil and placed in the trash, or just the liquid inside?  After that, is the silver-mirrored tube completely safe?

I mean at the scale you are working with it is very unlikely that any explosive material will result.
Adsorb the liquid with the soil.
Wash the test tube with some water and add the washings to the soil, let it dry out and put the cork back on it. This you can keep if you wish.
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Offline bottleneckfun

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Re: tollens silver mirror - and the dangers of it
« Reply #4 on: June 01, 2012, 08:31:19 AM »
Thank you very much for your *delete me*  I really appreciate your advice.  I have just one more question to be extra, extra clear, and to hopefully satisfy my paranoid self.  Over time, do the odds increase or decrease for forming a dangerous reagent?  In other words, given enough time, even with the small quantity I am using, might some dangerous chemical form?  Or on the flip side, are my chances decreasing so that perhaps every day, the odds halve that something bad will happen?

Offline Borek

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Re: tollens silver mirror - and the dangers of it
« Reply #5 on: June 01, 2012, 08:46:58 AM »
To make things safer don't use excess of ammonia and slightly acidify the solution after use to protonate ammonia, it will be not reacting with silver then.
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Offline discodermolide

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Re: tollens silver mirror - and the dangers of it
« Reply #6 on: June 01, 2012, 09:09:12 AM »
Thank you very much for your *delete me*  I really appreciate your advice.  I have just one more question to be extra, extra clear, and to hopefully satisfy my paranoid self.  Over time, do the odds increase or decrease for forming a dangerous reagent?  In other words, given enough time, even with the small quantity I am using, might some dangerous chemical form?  Or on the flip side, are my chances decreasing so that perhaps every day, the odds halve that something bad will happen?

The Tollens reagent is not too stable and no explosion will occur on the scale you are using.
As Borek said "slightly acidify the solution"
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Offline bottleneckfun

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Re: tollens silver mirror - and the dangers of it
« Reply #7 on: June 01, 2012, 04:25:50 PM »
Would household bleach work?  Should it be diluted, or is it already diluted enough?

Offline Borek

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Re: tollens silver mirror - and the dangers of it
« Reply #8 on: June 01, 2012, 04:39:37 PM »
Quite the opposite, adding bleach to the solution makes it more dangerous. Bleach is alkaline, and chlorine can react with ammonia, producing toxic chloramines. I doubt you would make serious harm to yourself as long as you are working with test glass amounts, still better to not try.

Acidify with hydrochloric acid (it will precipitate AgCl), or even acetic acid.
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Offline billnotgatez

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Re: tollens silver mirror - and the dangers of it
« Reply #9 on: June 03, 2012, 07:23:54 PM »
Quote
even acetic acid

commonly found in vinegar


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