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Topic: pH of HCL/NaOH Titration  (Read 1916 times)

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Offline defencegrid

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pH of HCL/NaOH Titration
« on: January 31, 2017, 12:21:59 AM »
I performed a titration with NaOH and HCl.  When I tested the pH of the NaOH/HCl solution which had reached the equivalence point, the pH was 1.1.  Shouldn't it be about seven?

Offline AWK

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Re: pH of HCL/NaOH Titration
« Reply #1 on: January 31, 2017, 12:54:18 AM »
Something gone wrong. Real pH of 0.1 M NaCl is ~6.9. May be you used water instead of NaOH?
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Offline defencegrid

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Re: pH of HCL/NaOH Titration
« Reply #2 on: January 31, 2017, 02:24:59 AM »
Something gone wrong. Real pH of 0.1 M NaCl is ~6.9. May be you used water instead of NaOH?

Yeah, that's what I thought.  I must of done something wrong.

Offline Borek

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Re: pH of HCL/NaOH Titration
« Reply #3 on: January 31, 2017, 02:28:41 AM »
I performed a titration with NaOH and HCl.  When I tested the pH of the NaOH/HCl solution which had reached the equivalence point, the pH was 1.1.  Shouldn't it be about seven?

Please elaborate on what you did, as what you wrote doesn't make much sense - how do you know you have reached the equivalence point, if that's typically done by controlling the pH, and your pH is so off?
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Offline defencegrid

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Re: pH of HCL/NaOH Titration
« Reply #4 on: January 31, 2017, 03:01:01 AM »
1M HCl in the burette and 10ml of NaOH in the conical flask with two drops of phenolphthalein.  Titrated until it turned colourless.

Offline AWK

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Re: pH of HCL/NaOH Titration
« Reply #5 on: January 31, 2017, 04:13:50 AM »
Check your pH-meter.
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Offline Arkcon

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Re: pH of HCL/NaOH Titration
« Reply #6 on: January 31, 2017, 05:13:04 AM »
Also, consider the possibility that you overshot the titration.  You should w to the palest pink color, a colorless state that returns to the palest pink when swirled, then the tiniest drop prevents any color from returning -- that's the endpoint.  Check it yourself, start with a neutral NaCl solution, take its pH, add 1 drop of HCl, is the pH still 7?
Hey, I'm not judging.  I just like to shoot straight.  I'm a man of science.

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