[H+] = [OH-]= 10-7 /, = lg 10-7 = 7. , . [H+] > 10-7/, < 7. 0 < < 7. [H+] < [] [H+] < 10-7 /, , > 7. : 7 < < 14.
() , . : , , . : 1) , 2) , 3) .
. , , , . , , ( ) . . .
, ; . , :
1) (NaCH3COO, Na2CO3, Na2S,);
2) (NH4Cl, FeCl3,, AlCl3,);
3) (NH4CN, NH4CH3COO).
, , : Na2SO4, BaCl2, NaCl, NaJ ..
+ . (. ).
1. 3, , 0,1 1,32%.
. (13), , a , 1,32/100=0,0132. ,
: 1,76×10-5.
2. 0,1 NH4OH, 1%.
. 1) NH4OH:
NH 4OH ⇄ NH4+ + OH
2) , 1 ∙a NH4OH ( = 0,1 /) :
[OH-] = ∙a = 0,1∙×0,01 = 1×10-3 /, , = 3
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3) : pH + pOH = 14, = 14 3 = 11.
: 0,1 11.
3. :
Pb(NO3)2 + KI
. 1) :
Pb(NO3)2 + 2KI PbI2¯ + 2KNO3
, PbI2.
2) ( , , , ):
Pb2+ + 2NO3 + 2K+ + 2I = PbI2¯ + 2K+ + 2NO3
3) , , , .. :
Pb2+ + 2NO3 + 2K+ + 2I = PbI2¯ + 2K+ + 2NO3
Pb2++ 2I = PbI2¯
, Pb2+ I, PbI2.
4. ZnCl2.
. ZnCl2 HCl Zn(OH)2, , . , .
I :
) ZnCl2:
ZnCl2 = Zn2+ + 2Cl
, , Zn2+.
) Zn2+ :
Zn2+ + H+OH ⇄ (ZnOH)+ + H+
) :
ZnCl2 = Zn2+ + 2Cl
Zn2+ + H2O ⇄ (ZnOH)+ + H+
ZnCl2 + Zn2+ + H2O ⇄ Zn2+ + (ZnOH)+ + 2Cl + H+
:
ZnCl2 + H2O ⇄ Zn(OH)Cl + HCl
HCl, < 7.
II :
.
) Zn(OH)Cl = (ZnOH)+ + Cl
) (ZnOH)+ + H+OH = Zn(OH)2 + H+
) Zn(OH)Cl = (ZnOH)+ + Cl
(ZnOH)+ + H2O = Zn(OH)2 + H+
Zn(OH)Cl + H2O = Zn(OH)2¯ + HCl
, HCl, ( < 7).
1. 8. .
() , , , . = + . , : () ( ).