Question

In feSO4 we took iron's valency as 2 but in fe2O3 we have taken iron's valency as 3
How can we decide where we should take 2 and ​ ​where 3​

Answer 1

EXPLANATION:

ONLY FE₂O₃ IS NOT FORMED BUT FE₃O₄ IS ALSO FOUND

BUT THE FACT IS THAT WE NORMALLY TAKE THE VALENCY THAT FORMS THE COMPOUND WHICH IS MOSTLY FOUND IN NATURE

THE SAME IS CASE WITH COPPER (CUPROUS AND CUPRIC) WHICH HAS VALENCY CU⁺¹ AND CU⁺²

BUTWE USE +2 IN CUSO₄  INSTEAD OF  +1

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