Oh you're right, my bad! i meant 2As3+ and 3S2-...
May i ask you a question... since there is the 2 as a stoichiometric coefficient in
2As3+ > 2AsO43- + 4e-
i have to multiply by 2 also H+ and H2O?
And also, to balance the charge, i have to consider the stoichiometric coefficient? i mean, the total charge of the products is -10 ( since 2As3- has a total charge of -6 ( i multiplied -3 x 2) and then 4e-) or -6?
and the same for the reagent... (2As3+) is it +3 or +6?
sorry for my bad explanation, i'm not very good in english haha, hope you understand