JEE Advanced 2022 Paper 2 Q12 Chemistry Inorganic Chemistry Metallurgy Medium

JEE Advanced 2022 Paper 2 · Q12 · Metallurgy

The correct option(s) related to the extraction of iron from its ore in the blast furnace operating in the temperature range 900 – 1500 K is(are)

  1. A. Limestone is used to remove silicate impurity.
  2. B. Pig iron obtained from blast furnace contains about 4% carbon.
  3. C. Coke (C) converts CO$_2$ to CO.
  4. D. Exhaust gases consist of NO$_2$ and CO.
JEE Advanced multi-correct — pick every correct option, then check.
Reveal answer + step-by-step solution

Correct answer:A, B, C

Solution

Blast-furnace chemistry (900–1500 K):

(A) Limestone (CaCO$_3$) decomposes to CaO + CO$_2$; CaO + SiO$_2$ $\rightarrow$ CaSiO$_3$ (slag), removing silicate (gangue) impurities. CORRECT.

(B) Pig iron from the blast furnace typically contains ≈4% carbon (plus small amounts of Si, P, Mn, S). CORRECT.

(C) Boudouard equilibrium at high T in the lower furnace: CO$_2$(g) + C(s) $\rightarrow$ 2 CO(g). Coke reduces CO$_2$ to CO. CORRECT.

(D) Blast-furnace exhaust gases are predominantly N$_2$ + CO + CO$_2$ (top-gas). NO$_2$ is NOT a normal exhaust component (and CO is present but the pair 'NO$_2$ and CO' is incorrect). (D) is WRONG.

Correct options: A, B, C.

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