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Chemistry Forums for Students => Undergraduate General Chemistry Forum => Topic started by: _cheers on November 07, 2009, 09:21:18 PM

Title: End points in strong-base titration of mixed acids
Post by: _cheers on November 07, 2009, 09:21:18 PM

A mixed aqueous solution of HCl and arsenic acid (H3AsO4; Ka1 = 4.90×10-3; Ka2 = 8.90×10-8) is titrated with 0.1000-M NaOH.
The first end point (ethyl orange indicator) is reached after 44.51 mL of NaOH has been added.
The second end point (thymolphthalein indicator) is reached after a total of 64.29 mL of NaOH has been added.

What quantity of HCl (units of mol or mmol) was present in the initial mixture?



What quantity of arsenic acid (units of mol or mmol) was present in the initial mixture?

Title: Re: End points in strong-base titration of mixed acids
Post by: Borek on November 08, 2009, 04:23:16 AM

Being a member for so long you already should know the rules - you have to try first.

Title: Re: End points in strong-base titration of mixed acids
Post by: _cheers on November 12, 2009, 12:09:34 AM

i have. i didnt post what i did is all. sheesh.