Church hyb solution questions

Glen Shearer gshearer at whale.st.usm.edu
Tue Mar 14 14:48:20 EST 1995


Anthony Tomlinson <tomlinson at pplros.demon.co.uk> wrote:
>
> In article <3j7due$mca at server.st.usm.edu> Glen Shearer,
> gshearer at whale.st.usm.edu writes:
> >
> >Just mix equal molar amounts.  0.5 mole/L monobasic + 0.5 mole/L
> >dibasic and there's your 1M stock.  For the hyb soln' mix up
> >2 parts NaPO4 stock, 1 part water, 1 part 20% SDS.
> >
> 
: surely if you do this the final solution is still 0.5M as the volume is
: double.
: In any case, the pH will not be 7. We mix 1M solutions of the two
: compounds until
: the pH is 7.2 this gives the 1M NaPi buffer. Note that it matters whether
: you
: add mon to dibasic or vice versa simply because you will require a much
: bigger
: volume of one than the other!! Off the top of my head I can't remember
: which way
: round it is :-) do a pilot to find out.
: 
: Mike Dalrymple

True, if you mix 0.5 M stock solutions.

What I was talking about was to just weigh out 0.5 M of monobasic
and dump it into a flask then weigh out 0.5 M dibasic, throw it in
and add water to a final vol of 1000 ml.

As I remember, the pH is actually not 7 but very close to it.

Regards,
Glen

[gshearer at whale.st.usm.edu]






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