Klarinet Archive - Posting 000462.txt from 1995/04

From: "Dan Leeson: LEESON@-----.EDU>
Subj: Re Michiya's response
Date: Wed, 26 Apr 1995 14:34:33 -0400

I am duplicating Mishiyo's response to me so that my comments can be
related to what I received. First, I am very grateful that Mishiyo took
the time to explain to me what Roger Shilcock's message was all about.
Second, and more important, I don't think I want to know more.

I am having trouble with fast tonguing and now I have to titrate spit, too?

I'm sorry I asked. (Though it was very thoughtful and helpful of
Mishiyo to try to get this stuff through my head. The fault is not
his, it is my head.)

> From: MX%"mnishino@-----.42
> Subj: Re: Re Roger Shilcock's reference to phenophthalein

>
> Dan Leeson wrote:
>
> > Roger, I found your comment unclear. First I don't know what the
> > substance is that you suggested I try saliva on. Second, I don't
> > know what is supposed to happen if I did try your suggested action.
> > And third, I would not know how to try the experiment that you
> > suggested.
> >
> > Would you run that one by us again with some greater detail, please?
>
> Phenolphthalein is an acid-base indicator used in acid-base titrations
> (when a strong acid is titrated with a strong base). It is a
> pinkish-purple color in basic solutions and colorless in acidic solutions
> (ie, colorless from pH range 1 to 8, pink/purple from pH range 10 to
> 13). The way indicators work is shown below:
>
> H+ = hydrogen ion
> In- = Indicator (ionized form)
>
> HIn --> H+ + In-
> <--
>
> HIn is Color 1
> In- is Color 2
>
>
> The molecular form of the indicator HIn is one color, and the ionized
> form In- is another color. Thus, when the equilibrium shown above is
> disturbed by removal of the H+, for example, (by adding excess base), the
> equilibrium shifts toward the products (right side) and the color of the
> solution changes from color 1 to color 2.
>
> I guess a way to determine the basicity of your saliva is to fill a buret
> with it (quite a task!) and to titrate it into a flask containing KHP
> (potassium acid phthalate--a primary standard often used to determine the
> concentration of bases), distilled water, and phenolphthalein.
>
>
> Regards,
> Michiya Nishino
> mnishino@-----.edu
====================================
Dan Leeson, Los Altos, California
(leeson@-----.edu)
====================================