Jawabanmu

2014-06-24T20:59:50+07:00
PH =9, pOH=5, OH- =10^-5
OH- = kb  \frac{mol basa}{mol garam} 

10^{-5} = 2.10^{-5} .  \frac{mol basa}{500x0,1} 

mol basa = 25

Molaritas =  25/500 = 0.05

semoga membantu!;)