Question

The oxidation state of $\mathrm{Cu}$ and $\mathrm{Fe}$in Copper Pyrites is :

• A. $+1\text{and}+2$
• B. $+1\text{and}+3$
• C. $+2\text{and}+6$
• D. $+2\text{and}+3$

Answer 1

The correct option is B

$+1\text{and}+3$

The explanation for the correct option

(B)$+1\text{and}+3$

Oxidation state:

• "The oxidation state of an element in a compound ascertained according to a set of rules formulated on the basis that electron pair in a covalent bond belongs entirely to a more electronegative element."

The oxidation state of $\mathrm{Cu}$ and $\mathrm{Fe}$in copper pyrites

• The formula for copper pyrites is ${\mathrm{CuFeS}}_2$.
• The oxidation state of copper in ${\mathrm{CuFeS}}_2$is $+1$.
• Consider the oxidation state of $\mathrm{Fe}$is $x$.
• $$\begin{gathered} +1+x+\left(-2\times 2\right)=0 \\ x=+3 \end{gathered}$$

Hence, the oxidation state of $\mathrm{Cu}$ and $\mathrm{Fe}$ in Copper Pyrites is $+1$, and $+3$.

The explanation for the incorrect option

The oxidation state of $\mathrm{Cu}$ and $\mathrm{Fe}$ in Copper Pyrites is $+1$, and $+3$.So,options (A), (C), and (D) are incorrect.

Hence, option (B) is correct. The oxidation state of $\mathrm{Cu}$ and $\mathrm{Fe}$ in copper pyrites is $+1$, and $+3$.