Test: Concentration of the Ore - JEE MCQ

The iron obtained from blast furnace is pig iron with carbon and impurities like Mn etc., in small amount.

This method is based upon the fact that the surface of sulphide over is preferentially wetted by oils while that of gangue is preferentially wetted by water.

ΔH = −ve, TΔS = + ve at any temperature

(A) Calcination For hydrated carbonate or bicarbonate ores ⇒(4) malachite, CuCO₃⋅Cu(OH)₂
(B) Roasting For sulphide ores ⇒ (1) galena, PbS
(C) Magnetic separation For magnetic ore or gangue ⇒ (2) magnetite, Fe₃O₄
(D) Carbon reduction of metal oxide It is done is furnaces on application of heat ⇒ (3) pyrometallurgy
The correct matching is (A)-(4), (B)-(1), (C)-(2), (D)-(3)

The explanations of given statements are as follows:
(i) In the extraction of Ag and Au, zinc is used as reducing agent.
2[Ag(CN)₂](aq) + Zn(s) ⟶ 2Ag(s) + [Zn(CN)₄]²⁻(aq)
Thus, statement (i) is correct.
(ii) Impure zinc can be refined by the process of distillation.
Thus, statement (ii) is correct.
(iii) Malachite, [Cu₂(CO₃)(OH)₂] is an ore of copper. Thus, statement (iii) is incorrect. Hence, correct option is (d).

Since silica is acidic impurity the flux must be basic.

CaO + SiO₂ → CaSiO₃

The metals and occur only in combined state, as these metals are available in nature mostly in the form of sulphide and oxides respectively.
and occur in both native and combined state.

Soluble complex
A layer of this zinc complex is formed on the surface of and due to this is prevented from the froth formation while PbS form froth.

Decomposition of carbonates and hydrated oxides.