Church hyb solution questions

["Alexander Kraev" bckraev at aeolus.ethz.ch]

In article <3jkn4u$gss at mserv1.dl.ac.uk>, "Edwin Fink" <fink at clinbio.med.uni-muenchen.de> writes:
>> Date:          8 Mar 1995 10:36:02 GMT
>> From:          bckraev%wawona at mserv1.dl.ac.uk ("Alexander Kraev" bckraev at aeolus.ethz.ch)
>> Reply-to:      bckraev%wawona at mserv1.dl.ac.uk ("Alexander Kraev" bckraev at aeolus.ethz.ch)
>> To:            "bionet.molbio.methds-reagnts mail newsgroup" <bionet-news at dl.ac.uk>
>> Subject:       Re: Church hyb solution questions
>

>> "1 M Na2HPO4" is 1M with respect
>> to sodium and 0.5 M in phosphate, so in practice you divide the MW by 2 and
>> weigh that out to be dissolved in 1 liter.  
>
>Sorry, Alexander, but I have to correct you:
>
>"1 M Na2HPO4" means that 1mol of Na2HPO4 is contained in 1 l of 
>solution, thus the solution is 2 M in  Na and 1 M in PO4. But, of 
>course, if you need a solution which is 1 M in Na than you titrate a 
>0.5 M Na2PO4 with phosphoric acid as originally described.
>Cheers,    Edwin
> 
Yes, Edwin, you are right. Thanks for correcting. I meant to say that the
usual meaning is one-molar-sodium (phosphate) is 0.5 M in the usual chemical
definition. I have been using this solution for more than 10 years and it is
a shame what I have written....
Cheers,

 
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Alexander Kraev, Ph.D.                 Internet: bckraev at aeolus.ethz.ch
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