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QJEEAdv23Chf4d0: JEE Advanced 2023 Chemistry - Class 12 JEEAdv23Chf4d0 Solution: The correct statement(s) related to processes involved in the…

The correct statement(s) related to processes involved in the extraction of metals is(are) :

Multiple Choice Options

  • A Roasting of Malachite produces Cuprite.
  • B Calcination of Calamine produces Zincite.
  • C Copper pyrites is heated with silica in a reverberatory furnace to remove iron.
  • D Impure silver is treated with aqueous KCN\mathrm{KCN} in the presence of oxygen followed by reduction with zinc metal.

Step-by-Step Verified Solution

(A) Roasting of malachite

CuCO3Cu(OH)2⟶Δ+O2CuO+H2O+CO2\mathrm{CuCO}_3 \mathrm{Cu}(\mathrm{OH})_2 \underset{+\mathrm{O}_2}{\stackrel{\Delta}{\longrightarrow}} \mathrm{CuO}+\mathrm{H}_2 \mathrm{O}+\mathrm{CO}_2

Roasting means that heating of substance in excess of oxygen. So cuprite Cu2O\mathrm{Cu}_2 \mathrm{O} is not produced. Hence, this statement is not correct.

(B) Calcination means heating in absence of air

ZnCO3 Calamine ⟶ΔZnO Zincite +CO2\underset{\text { Calamine }}{\mathrm{ZnCO}_3} \stackrel{\Delta}{\longrightarrow} \underset{\text { Zincite }}{\mathrm{ZnO}}+\mathrm{CO}_2

∴\therefore Statement is true.

(C)

CuFeS2+O2⟶ΔCu2 S+FeO+SO2FeO+SiO2⟶FeSiO2\begin{aligned}\mathrm{CuFeS}_2+\mathrm{O}_2 \stackrel{\Delta}{\longrightarrow} \mathrm{Cu}_2 \mathrm{~S}+\mathrm{FeO}+\mathrm{SO}_2 \\\\\mathrm{FeO}+\mathrm{SiO}_2 \longrightarrow \mathrm{FeSiO}_2\end{aligned}

∴\therefore Statement is true.

(D)

Ag+KCN+O2+2H2O⟶amp;4 K[Ag(CN)2]+4KOH2 K[Ag(CN)2]+Zn⟶amp;K2[Zn(N)4]+2Ag\begin{aligned}\mathrm{Ag}+\mathrm{KCN}+\mathrm{O}_2+2 \mathrm{H}_2 \mathrm{O} \longrightarrow & 4 \mathrm{~K}\left[\mathrm{Ag}(\mathrm{CN})_2\right] +4 \mathrm{KOH} \\\\2 \mathrm{~K}\left[\mathrm{Ag}(\mathrm{CN})_2\right]+\mathrm{Zn} \longrightarrow & \mathrm{K}_2\left[\mathrm{Zn}(\mathrm{N})_4\right]+2 \mathrm{Ag}\end{aligned}

Silver is obtained by reaction with Zinc

So, the above statement is true.

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