K2Cr2O7 KJ . . :
K2Cr2O7 + 6 KJ + 7H2SO4 Cr2(SO4)3 + 4K2SO4 + 3J2 +H2O
2Cr2O7-2 + 14H+ + 6e 2Cr+3 + 7H2O 2
2J- - 2e J2 6
I2 + 2Na2S2O3 2NaI + Na2S4O6
J2 + 2e 2J- 1
2S2O3- - 2e S4O62- 1
.
, Na2S2O3 0. 1-2 5%- KI 2-3 1 H2SO4. , 5 0,02 K2Cr2O7 ( ). , , 5 . (Na2S2O3) - , 4-5 - . , . 2-3 . ( 0,1 ) , :
/ | VK2Cr2O7 | NK2Cr2O7 | VNa2S2O3 | NNa2S2O3 | TNa2S2O3 |
C |
.
Na2S2O3 K2Cr2O7 , . N1V1 = N2V2 Na2S2O3 K2Cr2O7 , :
N Na2S2O3 =
CuSO4.5H2O.
2Cu2+ + 4Iˉ = 2CuI + I2
, Cu2+, I- , Cu+, (I) Cu+ (л 10-12). , - CuSO4.5H2O - (63,54) - (249,7 CuSO4.5H2O).
.
2,5 5%- KI. 5 CuSO4 ( ), 5 , Na2S2O3, , - . , ( CuI ). 2-3 .
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