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Chemistry Forums for Students => Analytical Chemistry Forum => Topic started by: Mexxgirl on March 09, 2005, 09:14:30 PM

Title: Questions about Volhard's Method
Post by: Mexxgirl on March 09, 2005, 09:14:30 PM

Hi everybody,
I'm new here! I found this site very helpful, thanks alot to the staff.

Now my questions:
1) Why diethyl ether is effective at preventing the end-point in Volhard's Method?
2) What would be the consequence of adding significantly more than 2ml of the ferric ammonium sulfate indicator?
 
and my 3rd question has nothing to do with Volhard's method:
What is the purpose of phosphoric acid in the determination of iron by permanganate titration?

Thank you very much and have a good day!!

Title: Re:Questions about Volhard's Method
Post by: Borek on March 10, 2005, 07:00:18 AM

Quote from: Mexxgirl on March 09, 2005, 09:14:30 PM

1) Why diethyl ether is effective at preventing the end-point in Volhard's Method?

Never heard it PREVENTS end-point :) But it mix with precipitate and make it less reactive.

Quote

2) What would be the consequence of adding significantly more than 2ml of the ferric ammonium sulfate indicator?

Formation of Ag(NH3)x complexes.
 

Quote

What is the purpose of phosphoric acid in the determination of iron by permanganate titration?

Fe/Cl complexes are yellow and they can mask (at least partially) endpoint. Fe/PO4 complex is colorless.

Title: Re:Questions about Volhard's Method
Post by: Mexxgirl on March 12, 2005, 01:50:08 AM

thank you very much

Title: Re: Questions about Volhard's Method
Post by: amcca064 on February 24, 2008, 11:02:14 PM

CHM 2354 by any chance?