NH3+HCl=NH4Cl剩余氨水浓度[NH3·H2O]=(0.2*0.1-0.1*0.1)/(0.1+0.1)=0.05mol/L生成的NH4+浓度[NH4+]=0.1*0.1/(0.1+0.1)=0.05mol/LKb=[OH-]*[NH4+]/[NH3·H2O]=[OH-]*0.05/0.05=1.8*10^-5,[OH-]=1.8*10^-5,pH=14-pKb=9.25