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PKa(H3O+/H2O) and PKa(H2O/HO-)
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Topic: PKa(H3O+/H2O) and PKa(H2O/HO-) (Read 18229 times)
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Shah
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Re: PKa(H3O+/H2O) and PKa(H2O/HO-)
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Reply #15 on:
February 14, 2011, 09:08:53 AM »
http://www.chembuddy.com/?left=pH-calculation&right=pH-buffers-henderson-hasselbalch
in this site it is written that if we mix 0.1 M of dichloroacetic acid of pKa=1.5 and 0.05 M NaOH. The pH won't be 1.5 . Proper pH value can be calculated using pH calculator - and it is 1.78. The reason is simple. Dichloroacetic acid is strong enough to dissociate on its own and equilibrium concentration of conjugate base is not 0.05 M (as we expected from the neutralization reaction stoichiometry) but 0.0334 M.
The question is: through my own calculations, the equilibrium concentration of conjugate base was approximately 0.0666 and not 0.0334, while the equilibrium concentration of the acid was 0.0334. Am i right or what is written in the site is right?
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Shah
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Posts: 32
Mole Snacks: +0/-0
Re: PKa(H3O+/H2O) and PKa(H2O/HO-)
«
Reply #16 on:
February 15, 2011, 08:41:42 AM »
What i meant to ask is: if we prepared a solution of 1 liter that contains 0.1 M of dichloroacetic acid of pKa=1.5 and 0.05 M NaOH. Can anybody calculate the concentration of conjugate base?
plzzzzzzzzzz help and thanks
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Shah
Regular Member
Posts: 32
Mole Snacks: +0/-0
Re: PKa(H3O+/H2O) and PKa(H2O/HO-)
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Reply #17 on:
February 15, 2011, 02:35:15 PM »
would the number of moles of the conjugate base be 0.0334 M or 0.0666? i would be thankful if you could show me the calculations?
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Shah
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Posts: 32
Mole Snacks: +0/-0
Re: PKa(H3O+/H2O) and PKa(H2O/HO-)
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Reply #18 on:
February 18, 2011, 07:49:46 AM »
can't anybody help
?
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PKa(H3O+/H2O) and PKa(H2O/HO-)