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Topic: Titration problem  (Read 4258 times)

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Offline aeromat2

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Titration problem
« on: January 31, 2011, 05:39:18 PM »
1) When 50.0mL of 0.10mol/L formic acid is titrated with 0.10mol/L sodium hydroxide, what is the pH at equivalence point? What is a good indicator for this titration?

First of all, are we able to use C1V1 = C2V2 here? If so, then I end up getting:

V1 = 0.05L <-- is this correct?
From there on, I am not sure what to do.
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Offline DevaDevil

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Re: Titration problem
« Reply #1 on: January 31, 2011, 05:55:27 PM »
well, first of all, what is an equivalence point?
then, what do you know about the Ka or Kb of formic acid?
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Offline aeromat2

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Re: Titration problem
« Reply #2 on: January 31, 2011, 06:03:05 PM »
Ka of formic acid is 1.7 x 10^-1.4
They are asking for the pH at equivalence point.
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Offline Borek

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Re: Titration problem
« Reply #3 on: January 31, 2011, 06:06:04 PM »
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Offline DevaDevil

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Re: Titration problem
« Reply #4 on: January 31, 2011, 06:06:40 PM »
nice link, Borel. explains it better than I ever could :)
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Offline aeromat2

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Re: Titration problem
« Reply #5 on: January 31, 2011, 06:10:22 PM »
Actually, I would proceed with that  but I dont know how I can obtain the volume for sodium hydroxide...
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Offline DevaDevil

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Re: Titration problem
« Reply #6 on: January 31, 2011, 06:13:34 PM »
again, what does the equivalence point mean?
This will also let you know what the volume of NaOH is.
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Offline aeromat2

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Re: Titration problem
« Reply #7 on: January 31, 2011, 06:26:06 PM »
What formula are they using when they say "Let's use the most simplified formula" with the [OH-] ?

http://www.titrations.info/acid-base-titration-equivalence-point-calculation
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Offline Borek

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Re: Titration problem
« Reply #8 on: February 01, 2011, 04:17:10 AM »
Quote from: aeromat2 on January 31, 2011, 06:26:06 PM
What formula are they using when they say "Let's use the most simplified formula" with the [OH-] ?

Not sure what the problem is, formula is listed exactly below the quoted text, as (2). Earlier in the text there are links to pages where derivation of the formula, and conditions that have to be meet for the formula to give correct results are explained.
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