Question

The oxidation state of Cu and Fe in $CuFe{S}_2$ are $+1$ and___respectively

Answer 1

Copper pyrite or $CuFe{S}_2$ exists as $C{u}_{2}S$. $F{e}_2{S}_3$ . The oxidation states of Cu and Fe are nominally considered to be +1 and +3 respectively

Now that we know how the mineral actually exists, we can easily calculate the required oxidation states. Sulfur exists in its -2 oxidation state as sulfide.

For $C{u}_{2}S$ to be neutral, Cu should exist in +1 oxidation state.

Let the oxidation state of Iron be x. In $F{e}_2{S}_3$ , since the molecule is neutral:

2(x) + 3(-2) = 0

Solving, we get x = +3