JEE Advanced 2014 · Paper 1 · Chemistry Q27

ChemistryMultiple correct+3Question 27 of 60

Upon heating with $\ce{Cu2S}$ , the reagent(s) that give copper metal is/are

\ce{CuFeS2}

\ce{CuO}

\ce{Cu2O}

\ce{CuSO4}

Answer and worked solution

Official answer: B, C, D

Cu₂S reduces oxygen-containing copper compounds to the metal (auto-reduction), with $\ce{SO2}$ formed:

(A) $\ce{CuFeS2}$ has no oxygen to remove the sulphide as $\ce{SO2}$ ; heating it with $\ce{Cu2S}$ does not give copper. No.
(B) $\ce{Cu2S + 2CuO -> 4Cu + SO2}$ . Yes.
(C) $\ce{Cu2S + 2Cu2O -> 6Cu + SO2}$ . Yes.
(D) $\ce{Cu2S + CuSO4 -> 3Cu + 2SO2}$ . Yes.

(B), (C), (D)

Topics:Extraction of specific metals

JEE Advanced 2014 · Paper 1, Chemistry question 27