PDA

View Full Version : A Question Please Help?


NeoTheOne
03-19-2006, 06:17 PM
If A soulution remains colourless when phenolphthalien is added, does this mean that the soloution is an acid? Explain?
JPaul
03-19-2006, 07:13 PM
If A soulution remains colourless when phenolphthalien is added, does this mean that the soloution is an acid? Explain?
Strictly speaking it means that it is not a base and may be acidic.
rnanker
03-19-2006, 07:26 PM
omg chemistry noob, i'm not gonna help you.
JPaul
03-19-2006, 07:29 PM
omg chemistry noob, i'm not gonna help you.
Oh go on, tell him it's because the molecule is colourless and the ion is pink, therefore the more pink the higher level of ions.
rnanker
03-19-2006, 07:32 PM
it's due to the refraction of the chemistry coat and the refractive index of the acid that causes the reflective properties of the dissicioative ions in the acid, which is more than the non-dissacioating ions in the alkalie.
JPaul
03-19-2006, 07:33 PM
it's due to the refraction of the chemistry coat and the refractive index of the acid that causes the reflective properties of the dissicioative ions in the acid, which is more than the non-dissacioating ions in the alkalie.
That's the ticket
rnanker
03-19-2006, 07:34 PM
no thats an answer
JPaul
03-19-2006, 07:37 PM
no, thats an answer
indeed
rnanker
03-19-2006, 07:37 PM
no an answer not a deed.
JPaul
03-19-2006, 07:38 PM
no an answer not a deed.
a deed, that's the answer
Gripper
03-19-2006, 11:29 PM
Phenolphthalein is an organic compound (C20H14O4) used as an acid-base indicator. The compound is colorless in acidic solution and pinkish in basic solution (with the transition occuring around pH 9).

Phenolphthalein does not dissolve very well in water, so for titrations it is usually prepared in alcohol solution. When adding a drop of indicator to an acid you will sometimes detect a slight cloudy white color. This is actually a precipitate of solid phenolphthalein, as the high local concentration exceeds the solubility product. It will usually dissappear if you shake the solution, since enough solvent becomes available to dissolve the solute.


Phenolpthalein was used for many years as the active ingredient in Ex-Lax. However, recent (and controversial) concerns about its possible carcinogenicity have caused it to be replaced with other substances in laxatives. There is no health hazard from the minute quantities used in titrations.