K2Cr2O7+KHSO3+H2SO4=?

Question

K2Cr2O7+KHSO3+H2SO4=?

Answer 1

(HSO3)- -2e- + H2O = 3H+ + (SO4)2-        | 2 | 6 | 3 |
(Cr2O7)2- +6e- + 14H+ = 2Cr3+ + 7H2O    | 6 |   | 1 |;

3(HSO3)- + (Cr2O7)2- + 5H+ = 3(SO4)2- + 2Cr3+ + 4H2O;
т.к. кол-во катионов H+ нечетное, удваиваем коэфф-ты:

6(HSO3)- + 2(Cr2O7)2- + 10H+ = 6(SO4)2- + 4Cr3+ + 8H2O;

2K2Cr2O7 + 6KHSO3 + 5H2SO4 = 5K2SO4 + 2Cr2(SO4)3 + 8H2O.