1. , , Mn+2 Mn+7.
.
MnO4 + 8H+ + 5ē = Mn2+ + 4H2O
1,51 . φ0= 0 0, φ0 > 0, , 1,51 , Mn2+ nO4
. , , 3+, , , . :
Co3+ + ē = Co2+; E0 = 1,82 ;
S2O82 + 2ē = 2SO42; E0 = 2,01 ;
O3 + 2H+ +2ē = O2+H2O; E0 = 2,07 ;
F2 + 2H+ + 2ē =2HF; E0 = 3,06 .
2. (, ) ?
. ,
O2 + 4H+ + 4ē = 2H2O; E0 = 1,229 B.
:
MnO4 + 8H+ + 5ē = Mn2+ + 4H2O; E0 = 1,51 B;
BrO3 + 6H+ + 5ē = 0,5Br2 + 3H2O; E0 = 1,52 B;
Cr2O72 + 14H+ + 6ē = 2Cr3+ + 7H2O; E0 = 1,33 B;
Co3+ + ē = Co2+; E0 = 1,82 B;
S2O82 + 2ē = 2SO42; E0 = 2,01 B.
, MnO4, Cr2O72, BrO3, S2O82 . , 3+, . , 3+, .
3. , .
. ,
2Ag + 2H+ = 2Ag+ + H2
, DG< 0 φ > 0. (1.27, 2.16):
Ag+ + ē =Ag;
2H+ + 2ē = H2;
, [H+], [Ag+] , φ > 0. [Ag+] = 1, [H+] = 1, :
;
;
lg < 27,1; < 7,9×1028 .
[Ag+] = 1, = 1, :
;
0,059 lg [H+] > 0,80;
lg [H+] > 13,6;
[H+] > 4,0×1013 /.
, ( !), . , . = 1, [+] = 1, :
|
|
;
0,059 lg [Ag+] < 0,80;
lg [Ag+] < 13,6;
[Ag+] < 2,5×10-14 /.
, , 10-14 /, [+] = 1 =1 . , . EAg+/Ag .
4. 2+ 3+ .
. 3+/2+ 1,82 , . 3+ (!) 2 2+. , :
.
, (!) 3+ 2+ (!), . ,
, , . ,
[Co(NH3)6]3+ + ē = [Co(NH3)6]2+; E0=0,10 B.
, 3+ , [o2+(CN)6]4 , [o3+(CN)6]3:
2 [o2+(CN)6]4 + 2H2O = 2 [o3+(CN)6]3 + H2 + 2OH.
5. :
Tl+ + ē= Tl; E01 = 0,34 B;
Tl3+ + 2ē = Tl+; E02 = 1,25 B
Tl3+/Tl.
. - .
Tl3+ + 3ē = Tl; E0X
, , Tl3+ (). . :
) 2Tl + 2H+ = 2 Tl+ + H2 (2H+ + 2ē = H2, E0 = 0 B)
DG0a= 2F(0E01) = 2FE01;
) Tl3+ + H2 = Tl+ + 2H+
DG0= 2F(E02 0) = 2FE02;
) 2Tl3+ + 3H2 = 2 Tl + 6H+
DG0= 6F(E0x 0) = 6FE0x.
"" "" "", :
DG0 =2DG0 DG0;
6FE0x = 4FE02 2FE01;
3E0x=2E02+E01;
.