Tip:
Highlight text to annotate it
X
So this is part B in the titration pair of what before the equivalence point we know the volume of the titrate and we know the volume of the week base
were mixing two solutions together so we have to do a dilution calculation and the results of that
dilution calculation are here in the initial row of the ice chart
so when you look at the amounts in a nice 1 to 1 ratio the smaller number in this case the acid is our women a reactant
so all of that gets consumed
so when she figure out
all your equilibrium concentrations in this ice chart next you want to identify what kind of chemicals you have so we still have some weak base
we have its kanji get acid
and we have some bromide
bromide is the kanji get of the strong acid hydra product so bromide is neutral
and that means with are weak base and conjugate acid we created a buffer
said notice this is different than in the strong acid strong base titration we never made a buffer when
you have one component strong in one component week you can create a buffer
because we're making the conjugate acid
and we still have some of the kanji get base left over
to one to recognize the have a buffer you can go to the Henderson us about formula
we have to do a little that'll work with this because we need the KA to calculate the PKA
and the KA is for this kanji get acid solar extra step to fine KA
we have to do a KW divided by KB
the KB value is given on the problem as 4.4 times tend to the negative for
so the KA is 2.27 times tend to the negative bowl of an
if you take the negative log of that you'll have the PKA and the PKA works out to be 10.64
then the other part of the Henderson also Bach the base concentration is
0.0527 and the acid was 0.2368
and we calculate this will get an answer of 9.99
notice we have more acid then we do base in this buffer and sewer PH will be lower than the PKA if we have more base
and acid than the PH one of them higher than the PK
strong acid strong strong acid
weak base
we can create a buffer if we had a strong base titrate and a weak acid
we could also create a buffer
we get a buffer when we haven't reached the equivalence point yet