, , , , .
-1 . - ( ).
- , (, , ). .
2. -:
+ + → + + +
.
1. , :
+ + → + + +
2. , , , , . , Cr, , :
+6 ē
-2 ē
+ + → + + +
2Cr+6 + 6 ē = 2Cr+3 () -
S-2 - 2 ē = S0 ()
3. ( ). () 3, 6 . :
2Cr+6 + 6 ē = 2Cr+3 1
+ S-2 - 2 ē = S0 3
2Cr+6 +3S-2 = 2Cr+3 + 3 S0
4. . . K2Cr2O7 Cr2(SO4)3 , .
K2Cr2O7 + 3H2S + H2SO4 = Cr2(SO4)3 + 3S + K2SO4 + H2O
5. . (Cr2(SO4)3, K2SO4), , 4 - (SO42-), , , 4. , 7:
K2Cr2O7 + 3H2S + 4H2SO4 = Cr2(SO4)3 + 3S + K2SO4 + 7H2O
, .
- ( ). , . , (), -. : +, - 2.
|
|
- :
1. (, HCl, H2SO4, HNO3) H+ , , H2SO4 2H+ +SO42-
, <10-3 (, H2S, HCN), .
2. (, LiOH, NaOH, KOH) - OH-, , + +OH-
, <10-3 (, NH4OH), .
3. . , KBr K+ +Br-1:
K Br3 K+ + Br3-1
K2Cr2O7 2 K+ + Cr2O72-
4. (, MnO2, FeO, Fe2O3, CO2, SO2, NO) .
5. 2 ( =1,8.10-16), 22 ( =1.10-25) , .
- :
1. - .
2. - .
3. , , .
4. , .
, , , -.
, , , -.
5. .
6. , , . : . , .
7. .
3. - - KMnO4 KNO2 , .