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Topic: Book Ka Value  (Read 14206 times)

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Offline Lou Lou

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Book Ka Value
« on: December 06, 2007, 06:48:16 PM »
Please could someone help me out i need a book Ka value for-

Bromocresol green

None of my books seem to have it and i can't find it on the net.

Many thanks.

Theresa  ;)
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Offline Borek

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Re: Book Ka Value
« Reply #1 on: December 06, 2007, 06:51:56 PM »
http://www.ph-meter.info/pH-measurements-indicators

Take middle of the range, better than nothing.
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Offline Lou Lou

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Re: Book Ka Value
« Reply #2 on: December 06, 2007, 07:12:00 PM »
Thanks very much for your reply but I need something a little more precise.
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Offline lemonoman

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Re: Book Ka Value
« Reply #3 on: December 06, 2007, 07:27:06 PM »
A search on Google Scholar:
http://scholar.google.com/scholar?hl=en&lr=&q=%22bromocresol+green+%28pKa%22

Shows that this article:
Tajima et al., 1998. Dyes and Pigments. 39 (2), 97-109.

cites the pKa as 4.68
Therefore the Ka is 10-4.68 = 2.09 × 10-5

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Offline Lou Lou

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Re: Book Ka Value
« Reply #4 on: December 06, 2007, 07:33:19 PM »
Thank you so much. I can use that and go to bed for the night now.



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Offline AWK

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Re: Book Ka Value
« Reply #5 on: December 07, 2007, 01:52:23 AM »
pKa 4.7
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