Solveeit Logo
Login

Question

Question: Upon heating with \(C{u_2}S\), the reagent(s) that give copper metal is/are : a.) \(CuFe{S_2}\) ...

Upon heating with Cu2SC{u_2}S, the reagent(s) that give copper metal is/are :
a.) CuFeS2CuFe{S_2}
b.) CuO
c.) Cu2OC{u_2}O
d.) CuSO4CuS{O_4}

Explanation

Solution

The answer to this are the reagents that can reduce copper sulphide. Because the metallic copper is formed from reduction of copper sulphide along with sulphur dioxide. So, the reagents from above that can reduce Cu2SC{u_2}S will be the favourable ones.

Complete step by step answer:
For this, we need to see the reaction of all the reagents with the Cu2SC{u_2}S on heating. The comparison of products will help us in finding our answer.
So, the first reagent given is CuFeS2CuFe{S_2}. This reagent upon heating with oxygen gives Cu2SC{u_2}S along with two molecules of FeS and sulphur dioxide. The reaction is written as -
2CuFeS2+O2→ΔCu2S+2FeS+SO22CuFe{S_2} + {O_2}\xrightarrow{\Delta }C{u_2}S + 2FeS + S{O_2}

So, this reagent does not give copper metal. Thus, this is not the correct answer.
The next reagent given is CuO. This CuO on heating produces Cu2OC{u_2}O. This Cu2OC{u_2}O reacts with Cu2SC{u_2}S to yield metallic copper. The reaction is -
4Cu→11000C2Cu2O+O24Cu\xrightarrow{{{{1100}^0}C}}2C{u_2}O + {O_2}
2Cu2O+Cu2S→Δ6Cu+SO22C{u_2}O + C{u_2}S\xrightarrow{\Delta }6Cu + S{O_2}

So, this can be the correct answer. Thus, the option b.) is the correct answer.
The third reagent is Cu2OC{u_2}O. The Cu2OC{u_2}O reacts with Cu2SC{u_2}S to yield metallic copper. The reaction is -
2Cu2O+Cu2S→Δ6Cu+SO22C{u_2}O + C{u_2}S\xrightarrow{\Delta }6Cu + S{O_2}
So, this can be the correct answer. Thus, the option c.) is the correct answer.

The fourth reagent is CuSO4CuS{O_4}. This CuSO4CuS{O_4} on heating produces CuO which on further heating gives Cu2OC{u_2}O. This Cu2OC{u_2}O reacts withCu2SC{u_2}S to yield metallic copper. The reaction is -
CuSO4→7200CCuO+SO2+12O2CuS{O_4}\xrightarrow{{{{720}^0}C}}CuO + S{O_2} + \dfrac{1}{2}{O_2}
4Cu→11000C2Cu2O+O24Cu\xrightarrow{{{{1100}^0}C}}2C{u_2}O + {O_2}
2Cu2O+Cu2S→Δ6Cu+SO22C{u_2}O + C{u_2}S\xrightarrow{\Delta }6Cu + S{O_2}

So, even this can be the correct answer. Thus, the option c.) is the correct answer.
So, the correct answer is “Option B, C and D”.

Note: The above reactions are thought to proceed via following mechanism.
Cu2S⇄2Cu++S2−C{u_2}S \rightleftarrows 2C{u^ + } + {S^{2 - }}
2Cu2O⇄4Cu++2O2−2C{u_2}O \rightleftarrows 4C{u^ + } + 2{O^{2 - }}
S2−+2O2−→SO2+6e−{S^{2 - }} + 2{O^{2 - }} \to S{O_2} + 6{e^ - }
6Cu+6e−→6Cu6Cu + 6{e^ - } \to 6Cu
The copper sulphide is reduced here to metallic copper with evolution of sulphur dioxide gas.