Question

A certain weak base has a Kb of 7.90 × 10-7. What concentration of this base will produce a pH of 10.33?

Answer 1

PH   = 10.33

POH = 14-PH

           = 14-10.33

            = 3.67

POH   = 3.67

-log[OH-] = 3.67

      [OH-] =10^-3.67   = 0.000214M

[OH-] = Kb*C

0.000214 = 7.9*10^-7 *C

0.000214*0.000214 = 7.9*10^-7 *C

C                              = 0.000214*0.000214/7.9*10^-7    = 0.058M >>>> answer