［OH－］=（0.1×1.8×10*-5）²=1.34×10*-3［H＋］=1×10*14/1.34×10*-3=7.5×10*-12PH=－lg7.5×10*－12=11.1
pOH=(pKb-lgc)/2=(4.74 -(-2))/2=3.37pH=14-3.37=10.63
