Chemistry - Metallurgy Question with Solution | TestHub

The chemical formula for copper pyrite (chalcopyrite) is CuFeS₂, which can also be represented as a combined form of sulfides like Cu₂S ⋅ Fe₂S₃. In this compound structure, copper (Cu) exists in its lower stable oxidation state, giving $x=+1$.

Consequently, iron (Fe) balances the sulfide framework by adopting an oxidation state of $y=+2$. Substituting these values into the expression gives:

$$x+y=1+2=3$$