Re: Need Ozone

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "default by way of Terry Fritz <twftesla-at-uswest-dot-net>" <moya-at-primus.ca>

Hello Dr Cadd

Thank you I will try this approach w/ the spiked salt solution may be this
will provide enough sodium
iodine for the reaction.

As for the rubber test - This test is of particular interest to me since I
might be able to monitor
the increase or decrease of O3 %  by observing an accurate time exposure
ratio if standards were used
- If this works it might also be of interest to those experimenting with
quenching methods to gauge
the O3 %  w/ there new method.

Cheers

Tom

Tesla list wrote:

> Original poster: "Dr. Duncan Cadd by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <dunckx-at-freeuk-dot-com>
>
> Hi Tom, Ed, Jeff, All!
>
> >Same lack of resources - So I saturated a small amount of hot water
> w/ salt
> >i.e. ( .001%)
> >sodium iodide an mixed it with starch - Nothing happened so I
> thickened the
> >solution w/ more
> >starch nothing happened - Then I thin the solution w/ more sodium
> iodide
> >still nothing - Guess I
> >need a more concentrated form of sodium iodide or blue paper for any
> results.
>
> You may be right as this is indeed very dilute iodide - incidentally,
> you didn't mention that you'd exposed this solution to ozone but I
> assume you soaked a bit of paper in it and hung it up near a working
> coil.  The iodide/starch alone will do nothing.  It needs the presence
> of ozone to liberate elemental iodine from the iodide by oxidation of
> the iodide ion, as per Jeff's original posting.  Then you get the
> intense coloration with starch.  If you have any tincture of iodine in
> your household medicine chest or first aid kit you'll see what I mean.
> That ought to give an instant dark blue/black colour with starch.
>
> However, it may also be that the chloride ions or the anti-caking
> agents in the salt are interfering with things, I seem to recall (from
> inorganic chemistry a long time ago) that iodine can form a complex
> with other halide ions.  If you do have some iodine tincture and you
> do see the blue/black colour with starch, you might try spiking a
> small quantity of tincture with salt solution and see if it still
> works with the starch :-)  If it doesn't, you know what's going on!
>
> But the test Jeff posted does work, I can dimly remember doing this
> over 25 years ago.  Perhaps for this purpose you really do need pure
> (99%+) sodium or potassium iodide.  I don't know what degree of
> success you are likely to have if you go asking for say an ounce of
> this from your local chemist's shop.  If you tell them it's being used
> to monitor for toxic levels of ozone they may be sympathetic ("health
> & safety" is a great moral bludgeon phrase, cunningly wielded you can
> extract almost anything from anybody.)  Of course, if the O3 test
> strips you found on the web are cheap enough, that's obviously the way
> to go,  but you may be faced with the situation that one box of test
> strips only costs pennies, but there's a minimum order of $100, one
> can but try.
>
> The other test used for ozone detection, though less sensitive and
> less rapid than the above, was to stretch a very thin (paper thin)
> piece of natural rubber tightly over a frame a couple of inches in
> diameter and leave it where it would be exposed to the ozone.  O3
> attacks the double bonds in the rubber to form molozonides and
> ozonides plus their decomposition products, and it becomes at first
> sticky, then very brittle and its transparency decreases, becoming
> white and opaque, which effects are intensified when the bonds are
> stressed.  Nitrogen oxides don't have this effect.  The thinner the
> rubber film, the more sensitive this test is.  Before the invention of
> direct reading ozone meters, this was used for occupational health and
> atmospheric monitoring many years ago.
>
> Dunckx