J.R. S. answered • 04/09/21
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Let the weak base be B
B + H2O ==> BH+ + OH-
Kb = [BH+][OH-] / [B]
From pH = 10.70 we can find the [OH-] as follows:
pOH = 14 - pH = 14 - 10.70 = 3.3
[OH-] = 1x10-3.3 = 5.0x10-4 M
Kb = (5.0x10-4)(5.0x10-4) / 0.0910
Kb = 2.74x10-6
J.R. S.
tutor
The consumption of B is less than 0.6% so can be ignored. And I repeated the calculation of (5.0x10-4)(5.0x10-4) / 0.0910 and still obtain the same answer. Can you please explain why it is incorrect?
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03/10/23
Mason P.
You forgot to account for the consumption of B resulting in Kb=2.76E-8. Furthermore if for some reason that wasn’t the proper logic your number is arithmetically wrong as well with the actual results of the calculation you performed being 2.75E-803/10/23