Background
Thoughtshop Foundation a non-profit organisation based in Kolkata,
India. We develop educational tools for other developmental
organsiations. For more information please visit
www.thoughtshopfoundation.org.
We are in the process of developing a kit for HIV/AIDS awareness in
schools. The kit comprises games and activities that can be conducted
by teachers or young people themselves.
One of the activities in the kit involves an alkali and an indicator.
The alkali is dissolved in a few transparent cups that participants
are given. The idea is that it is impossible to tell just by looking
which cup has alkaline water.
To ensure ease of use, we are using purified NaOH pellets (produced by
E.Merck India, product ID 17573). In the kit the pellets are
re-packaged into small plastic bottles. Each bottle fills up with
about 20 pellets.
The Problem
The NaOH pellets are delinquescent and they lose shape and get stuck
to each other after about a week even in a bottle sealed with teflon
tape.
· Is there any inert "coating" that the pellets can be given to reduce
contact with air without significantly affecting the purpose of the
activity?
· Is there any other way to dry-package small quantities of alkali
(e.g. paper strips, cotton buds)
· Is there any alternative agent-indicator combination that will meet
our requirements (that is : can be dry packaged, invisible in water
until indicator is added)
What we have considered
The bottle with pellets could be packed with common salt to minimise
trapped air, and absorb some of the moisture.
We do not know how the salt will react with the pellets over a long period of time.
Thanks for your help!! |
Clarification of Question by
santayan-ga
on
12 Aug 2004 23:55 PDT
We have tried out some of your suggestions, thanks a lot.
dr_bob-ga K2C03 works, but we got powder, which is cumbersome, trying
to get some more user friendly form. If we find it, it will be the
best alternative so far.
BTW we had reasonable succes by dissolving NaOH in Glycerine. it is
easier to handle. Trying to work out the concentration now.
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