A certain weak base has a Kb of 9.00 × 10-7. What concentration of this base will produce a pH of 10.34?

Answer 1

pH + pOH = pKw = 14.
You know pH and pKw, solve for pOH, then
pOH = -log(OH^-) and solve for (OH^-).
..........BH + HOH ==> BH2^+ + OH^-
Kb = (BH2^+)(OH^-)/(BH)
You know (OH^-) = (BH2^+) and Kb, solve for (BH) = concn of base.