solution of 0.1molar NH4OH and 0.1 NH4CL ph=9.25 calculate kb for NH4OH?

Answer 1

pH = pKa + log (base)/(acid)
Substitue and solve for pKa, then convert pKa to pKb, then to Kb
pKa + pKb = pKw = 14.
and pKb = -logKb

Answer 2

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Answer 3

4.75