Homework Help: Chemistry 111

Posted by Alix on Tuesday, April 5, 2011 at 3:15pm.

a)For the titration of an acid analyte with a NaOH titrant, a phenolphthalein endpoint will change from colorless to pink. If the "pink" resulted from perhaps only a half-drop(or less) of NaOH titrant and the Erlenmeyer flask is set aside on the laboratory bench, the pink color may disappear after an hour or so. Explain.

b) Explain why it is quantitatively not acceptable to titrate each of the vinegar samples with the NaOH titrant to the same dark pink endpoint.

Chemistry 111 - DrBob222, Tuesday, April 5, 2011 at 6:23pm
a) My experience is that it doesn't take an hour or so but the pink color disappears after a VERY short time. The reason is absorption of CO2 from the air which produces an acid.

b) You probably should have explained a little better since we don't know what you're doing experimentally; however, I assume the question is asking why not titrate to a DARK pink end point. The reason is that the eye is more sensitive to the faintest pink visible (from colorless) versus the intensity or hue of a darker pink color.
Chemistry 111 - kisha, Wednesday, June 22, 2011 at 8:45pm
atom o has how many valance electrons?
Chemistry 111 - Anonymous, Friday, March 23, 2012 at 12:14pm
write an account of youe daily routine that would include measurements in metric.Use metric only to describe

Answer this Question

Related Questions

chemistry - Hi I have this problem I have no idea where or what to do. 25.00 mL ...
CHEMISTRY - Explain why it is quantitatively not acceptable to titrate each of ...
acid-base titrations - what is it important to keep the NaOH solution covered at...
chem - Help with this one please? If you place a piece of blue litmus paper in ...
Chemistry - Phenolphthalein is an indicator that changes colour to pink/purple ...
chemistry - If the end point in the titration of oxalic acid with NaOH solution ...
Chemistry - Antacid tab is dissolved in water and a few drops of phenolphthalein...
Phenolphtalein vs Methyl Orange (check my reasonin - Why can either ...
Chemistry-Confused by titration!! - If a 28 mLs of a 0.25 molar NaOH solution is...
AP Chemistry - Hi! For a strong acid-weak base titration what's an example ...

For Further Reading

First Name:
School Subject:
Answer: