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Add 30mL of 1.00 NaOH to 100 mL of 0.50M HOAc (pKa = 4.74)
Using the Henderson-Hassel equation it would be
pH = 4.74 + log [30/70]
What about my equation is wrong? Since log is less than 1 it would suggest pH is greater than pKa, but that is false.
I know the pH should in fact be greater than pKa since we're adding more than 25mL of NaOH, so we are past half equivalence -- meaning our pH is greater than pKa. But my use of the equation isnt matching up.
Thanks in advanced.
EDIT*-----Figured it out.. SO STUPID!
Must put log [moles CB] / [moles CA]
So I had to multiply concentration by volume first, then do the appropriate subtractions from the moles.
Using the Henderson-Hassel equation it would be
pH = 4.74 + log [30/70]
What about my equation is wrong? Since log is less than 1 it would suggest pH is greater than pKa, but that is false.
I know the pH should in fact be greater than pKa since we're adding more than 25mL of NaOH, so we are past half equivalence -- meaning our pH is greater than pKa. But my use of the equation isnt matching up.
Thanks in advanced.
EDIT*-----Figured it out.. SO STUPID!
Must put log [moles CB] / [moles CA]
So I had to multiply concentration by volume first, then do the appropriate subtractions from the moles.
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