Among the reactions (a)-(d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are: (a) $\mathrm{CaO}+\mathrm{SiO}_{2} \longrightarrow \mathrm{CaSiO}_{3}$ (b) $3 \mathrm{Fe}_{2} \mathrm{O}_{3}+\mathrm{CO} \longrightarrow 2 \mathrm{Fe}_{3} \mathrm{O}_{4}+\mathrm{CO}_{2}$ (c) $\mathrm{FeO}+\mathrm{SiO}_{2} \longrightarrow \mathrm{FeSiO}_{3}$ (d) $\mathrm{FeO} \longrightarrow \mathrm{Fe}+\frac{1}{2} \mathrm{O}_{2}$

JEE Main · 2020 · 08 Jan 2020 · Shift 2 · General Principles and Processes of Isolation of Metals

Among the reactions (a)-(d), the reaction(s) that does/do not occur in the blast furnace during the extraction of iron is/are:
(a)

CaO + SiO_{2} ⟶ CaSiO_{3}

(b)

3 Fe_{2} O_{3} + CO ⟶ 2 Fe_{3} O_{4} + CO_{2}

(c)

FeO + SiO_{2} ⟶ FeSiO_{3}

(d)

FeO ⟶ Fe + \frac{1}{2} O_{2}

Answer: (A)

In the blast furnace the lime acts as a flux,

CaO + SiO X_{2} CaSiO X_{3}

, and carbon monoxide reduces the ore in stages,

3 Fe X_{2} O X_{3} + CO 2 Fe X_{3} O X_{4} + CO X_{2}

, so both of these do occur. The step

FeO + SiO X_{2} FeSiO X_{3}

is deliberately prevented, since the lime slag keeps iron out of the silicate, and the thermal breakup

FeO Fe + \frac{1}{2} O X_{2}

does not happen in the reducing atmosphere, where

FeO

is instead reduced by

CO

. So the reactions that do not take place are

FeO + SiO X_{2} FeSiO X_{3}

and

FeO Fe + \frac{1}{2} O X_{2}

JEE Main · 2020 · 08 Jan 2020 · Shift 2 · Single correct option