例2用EDTA滴定Zn2至化学计量点附近, ph=11.00, NH31=0. 10mol L- 计算 lg a Ln(NH3) 1+INH31B+[ B2+INH313B3+INH314B =1+10-100+227+102.00+4.61+103.00+1.01+104.009.6 J+1032+102+10401+10506=10510 查附录6,pH=11.00时,10zmOm=5.4 1ga2n=g(am(NH+amoH1)=g(1051+10541)=10566 例2 用EDTA滴定Zn2+至化学计量点附近, pH = 11.00，[NH3 ]=0.10mol·L-1 , 计算 lg Zn Zn(NH3)= 1+[NH3 ]1+[NH3 ] 2  2+[NH3 ] 3  3+[NH3 ] 4  4 =1+10-1.00+2.27+10-2.00+4.61+10-3.00+7.01+10-4.00+9.06 =1+101.27+102.61+104.01+105.06=105.10 查附录III.6 , pH=11.00时, lg Zn(OH)=5.4 lg  Zn= lg( Zn(NH3)+  Zn(OH)-1)=lg(105.1+105.4 -1)=10 5.6