例4计算pH20和50时的gK(ZnY) Zn Y ZnY OH H a Zn(oh y( ZnY(H lg k(ZnY)=lg K(ZnY)+IgazmY(H)& did(oH)\d(H) lgK(ZnY)=16.5, IgK(ZnHY)=3.0
11 例4 计算pH2.0和5.0时的lgK (ZnY) Zn + Y ZnY α Zn(OH) α Y(H) α ZnY(H) ( ) ( ) ZnY H Zn OH Y H ( ) ( ) ( ) lg ' ZnY lg ZnY lg lg lg K K = + − − ( ) ( ) H lg ZnY 16.5, lg ZnHY 3.0 K K = = OH- H+ H+
pH=20, gaY(m)=138(录Ⅲ5, Ig a zn(Oh=0(附录m6) aznY(田=1+|HK(ZnHY)=1+102030=1010, Ig a ZnY(=1.0 lgr(znY)=IgK(ZnY)+IgaznYH) -Igaz Zn(OH)"ga, 165+10-0.0-138=37 pH=5.0, Iga =6.6, gaze m(OH)=0.0 gK(ZnY=lgk(ZnY)-Igdr(H)9.9 12
12 pH=2.0, ( ) ( ) ZnY H Zn OH Y H ( ) ( ) ( ) lg ' ZnY =lg ZnY +lg -lg -lg K K =16.5+1.0- 0.0-13.8 = 3.7 ( ) ( ) ( ) Y H( ) Y H Zn OH lg = 6.6, lg = 0.0 lg ' ZnY = lg ZnY pH = 5. - lg , 9 0 K K = 9. ( ) lg Y(H)=13.8 (附录III.5), lg Zn(OH)=0 (附录III.6) ZnY(H)=1+[H]KH(ZnHY)=1+10-2.0+3.0=101.0 , lg ZnY(H)=1.0