The pH of a .150M solution of a weak base is 10.98. Calculate the pH of a .0400 M solution of the base.
The wording of this question is confusing me, I am not sure if I understand.
From the first information , pH --- get pOH and conc OH- (equilibrium)
write RICE table for B . You know X so calculate Kb
Use this Kb and make another RICE table for second concentration of the same base.
Get the value of X which is OH- (at equilibrium)
Get pOH and then pH .