The ph of a 0.24 m solution of dimethylamine is 12.01. calculate the kb value for dimethylamine.

1 - First we will get the value of POH from:

PH + POH = 14

and we have PH = 12.01

∴ POH = 14 - 12.01 = 1.99

2 - Then we need to get the concentration of OH:

when POH = - ㏒[OH]

1.99 = - ㏒[OH]

∴[OH] = 0.01 M

now we have the concentration at Equ by subtracting from the initial concentration of OH = 0.24 M

∴ [OH] = 0.24 - 0.01 = 0.23 M

∴ Kb = (0.01) ^2 / 0.22977 M

∴ Kb value = 4.4 x 10^-4