-- D1 + A2 A1 + D2, - , (). . 5.1 , .
. 5.1. -- ; .
( ) , .
- Mz+│M, - . (S solution) ( - metal)
M z + (S) + z e M (M); M z +/ z + e M/ z, (5.1)
z e . , ( (5.1)).
. 1) . , , , . 2) . , , . | |
. 5.2. . |
- , i - φ. , (5.2)
F = 96485.3 / ( ). , , , (μ i) zi φ.
, (5.1) M z +| M
, (5.3)
. (5.2) (5.3)
. (5.4)
(5.5)
: . (5.5)
(5.6)
(, , )
(5.7)
() ( ) ( ˚) ( ) . , , , , 1.
|
|
(. 5.3) : , , . : G | G2 | Pt ( - ).
() 1/2 G2 + e G, G ≡ Cl ;
() G+ + e 1/2 G2, G+ ≡ H+.
( ()), : . (5.8) , , . (5.8) . | |
. 5.3. | . |
, , f, .
() , () - :
, (5.9)
f a = 1.
- | | (X | MX | M) . MX , X, - M. - : Cl | AgCl | Ag. - Cl | Hg2Cl2 | Hg. MX + e‾ ↔ M + X‾ , (5.10): | |
. 5.4. | | |
, (5.10)
,
, (5.11)
. (5.12)
- - -, . - , .
- A2+, A+ | M, M - A2+ + e = A+.
: Fe3+ + e Fe2+ - .
, ,
, (5.13)
. (5.14)
, . .
MX , , , M+, : α β . "" - , | |
. 5.5. . |
K+, Na+ Cl¯. K+ 10‑30 , " ". (). . Dj(in,ex) = 0,07 .
|
|
0,02 , Na+. Dj(in,ex), .., .
.
. 5.6. . | . 5.7 . . |
. 5.7 . . |
, , .. (. 5.6).
Pt, H2 | HCl | AgCl, Ag, Pt
, (L) (R), , .
( , ) . 5.7.
Pt, H2 | HCl(m L) | HCl(m R) |H2, Ag, Pt
(. 5.7), KCl . K+ Cl¯. , " " ‑ . .
, .
, ( - ).
Pt, H2 | HCl(m L)|AgCl, Ag...Ag, AgCl | HCl(m R) | H2, Pt
||.
, ( ) , (). ... E. . | |
. 5.8. ... . |
, , :
(5.15)
1) ... (5.16), , , .
(5.16)
, , .
2) ( ): ... E R E L
, ( , ).
Pt | ML | S | MR | Pt | : | Pt | H2() | HCl(m) |AgCl, Ag | Pt | ||
L | R | L | R | |
. , , , . , , . . : , ., , , m.
|
|
, , , , .
.
E > 0, . (5.17+)
E < 0, . (5.17¯)
L + R+ = L+ + R ... L | L+ | R+ | R . ( R L.):
1. ( ). , ( ). , , .
2. ( ) , ... ( ).
3. , ... ( ).
L+ + e = L | EL | |
R+ + e = R | ER | |
R+ L+ = R L | E = ER - EL | |
R+ + L = R + L+ | E > 0 ; E < 0 . |
( ) - .
+ | L+ + e R+ + e | L EL R ER | |
L + R+ = L++ R E = ER - EL |
-
Fe + 2 H+Cl¯ (aq) + 1/2 O2 = Fe2+Cl¯2(aq) + H2O
L: 1/2 Fe2+ + e ← 1/2 Fe -0,44
R: H+ + e + 1/4 O2 → 1/2 H2O 1,229
E = 1,229 (-0,44) =1,669
.
L | L+ || R+ | R, L + R+ = L+ + R. ..., (5.16), (5.7) (5.18).
, (5.18)
. (5.19)
... ... (5.19), , ai = 1.
, .
, , . (). , ; , 1 , 298,15 (25 ).
|
|
: H+( =1) | H2(f =1 ), Pt; E (H+ | H2) º 0. (5.20)
, , - . E ( ) = E R E () = E R
. , . , , , .
Cu+ + e = Cu, E (Cu+ | Cu) = 0,521
- - , .
: () Zn () 1) Cu2+, 2) Mg2+?
: 1/2 Zn2+ + e ↔ 1/2 Zn; E = ‑0,763
: 1) 1/2 Cu2+ + e → 1/2 Cu; ∆E = 0,337 - (‑0,763) > 0 .
2) 1/2 Mg2+ + e ← 1/2 Mg; ∆E = -2,37 - (‑0,763) < 0 .
, : Li, Rb, K, Mg, Al, Mn, Zn, H, Cu, Pt, Au.
() , .
, .. , .
, , ... Pt, H2 (1 ) | HCl(m) | AgCl | Ag, Pt. ..., (5.15) (5.16) (5.11) ((5.9), )) (5.20), :
(5.21)
, - 1:1 , m - .
E (m) , (m → 0) E . g m .