- - ( ).
- , . , , .
(, Fe, N2, O3) .
:
Li Be
Na Mg
K Ca Zn
Rb Ag +1 Sr Cd +2
Cs Ba
Fr Ra
Al +3 F 1
(H) +1; ( , , NaH, CaH2) 1.
(O) 2; (HOOH) 1.
, , K2Cr2O7. +1, 2. :
+1 2
K2Cr2O7
, .. K2Cr2O7 : 2∙(+1) + 2∙ + 7∙(2) =0.
, = +6.
- MnO4: ; 2. .. - 1, MnO4 1:
2
[MnO4]
1∙ + 4∙(2) = 1
= +7.
, ; . , , .
- : - ( ). :
4 Fe + 3 O2 2 Fe2O3
Fe Fe3+ + 3e (× 4)
O2 + 4e 2 O2 (× 3)
- ( ) , , , . - - :
1) , ;
2) - ( , , , ) , , - ; ;
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3) , , , , ( );
4) , - , H2O, H+, OH; (. );
5) (), ;
6) - - , ;
7) .
.
3.1 K2Cr2O7 + N2H4 + H2SO4 N2 + Cr2(SO4)3 + K2SO4 + H2O.
1) Cr+6 Cr+3 N2 N0
2) 2K++Cr2O72+N2H4+2H++5SO42 N2+2Cr3++SO42+2K++SO42+H2O
3) Cr2O722 Cr3+ ; N2H4 → N2 :
Cr2O72 2 Cr3+
N2H4 N2
4) Cr2O72 2 Cr3+ , , 7 H2O, 14 H+ ( H2SO4, .. ):
Cr2O72 + 14 H+ 2 Cr3+ + 7 H2O
, .
- - , , , 2 , +.
- , (N2H4) , N2H4 N2 . , 4 H+:
N2H4 N2 + 4 H+
:
- - , , , +.
5) . Cr2O72+14 H+ 2 Cr3+ + 7 H2O
+12 (14 H+ Cr2O72), +6 (2 Cr3+; , ). 6 ( ):
Cr2O72 + 14 H+ + 6 e 2 Cr3+ + 7 H2O
N2H4 N2 + 4 H+ N2H4, , ; +4 ( H+). 4 :
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N2H4 N2 + 4 H+ + 4 e
6) , . 2, 3 ( , 12):
Cr2O72 + 14 H+ + 6 e 2 Cr3+ + 7 H2O ´ 2
N2H4 N2 + 4 H+ 4e ´ 3
2 Cr2O72 + 3 N2H4 + 28 H+ 4 Cr3+ + 3 N2 + 12 H+ + 14 H2O
+ 2 , :
2 Cr2O72 + 3 N2H4 + 16 H+ 4 Cr3+ + 3 N2↑ + 14 H2O
7) - - , .
2 K2Cr2O7 + 3 N2H4 + 8 H2SO4 3 N2 + 2 Cr2(SO4)3 + 2 K2SO4 + 14 H2O
3.2 KMnO4 + NH3 N2 + MnO2 + KOH + H2O
1) Mn+7 Mn+4 N3 N0
2) 3) K+ + MnO4 + NH3 N2↑ + MnO2 + K+ + OH + H2O
MnO4 MnO2
2 NH3 N2
4) ( KOH ), OH H2O, .. . - MnO4 MnO2 . .
- - , , , OH, H2O.
MnO4 MnO2, 2 , 4 OH, 2 H2O:
MnO4 + 2 H2O MnO2 + 4 OH
- (2 NH3 N2) .
:
- - , , , H OH, 2.
2 NH3 N2 H. , 6 OH, 6 H 6 , :
2 NH3 + 6 OH N2 + 6 H2O
5) .
MnO4 + 2 H2O + 3 e MnO2 + 4 OH
2 NH3 + 6 OH N2 + 6 H2O + 6 e
6) MnO4 + 2 H2O + 3e MnO2 + 4 OH 2
2 NH3 + 6 OH N2 + 6 H2O + 6e 1
2 MnO4 + 4 H2O + 2 NH3 + 6 OH 2 MnO2 + N2 + 8 OH + 6 H2O
2 MnO4 + 2 NH3 2 MnO2 + N2 + 2 OH + 2 H2O
7) 2 KMnO4 + 2 NH3 2 MnO2 + N2 + 2 KOH + 2 H2O
- - , , CH3CHO CO2 H, O, : , . CH3CHO CO2 :
CH3CHO 2CO2
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: + 3H2O + 6H+
: + 4H+
CH3CHO + 3H2O 2CO2 + 10H+
: CH3CHO + 3H2O 2CO2 + 10H+ + 10e
Cr(OH)3 CrO42 :
Cr(OH)3 CrO42
: + 2OH + H2O
: + 3OH + 3H2O
Cr(OH)3 + 5OH CrO42 + 4H2O
: Cr(OH)3 + 5OH CrO42 + 4H2O + 3e
, , H, O, OH:
1) Zn [Zn(OH)4]2 2) P H2PO2
Zn + 4OH [Zn(OH)4]2 P + 2OH H2PO2
Zn + 4OH [Zn(OH)4]2 + 2e P + 2OH H2PO2 + e
, , (.. ), , ; .