Ferric oxide in blast furnace's upper half is mainly reduced by:

The correct answer is Option (1) → \(CO\)

In the blast furnace, coke burns near the bottom to give CO and heat. The CO rises to the upper part, where the temperature is lower (500–800 K), and reduces the iron oxides coming down from the top in steps:

    \( \displaystyle \ce{3Fe2O3 + CO} \xrightarrow{\text{500-800 K}} \ce{2Fe3O4 + CO2} \)

    \( \displaystyle \ce{Fe3O4 + 4CO} \xrightarrow{\text{500-800 K}} \ce{3Fe + 4CO2} \)

    \( \displaystyle \ce{Fe2O3 + CO} \xrightarrow{\text{500-800 K}} \ce{2FeO + CO2} \)

So in the upper half the main reducing agent is carbon monoxide.

Why the other options are incorrect

• Option (2) C — Incorrect. Coke reduces FeO directly only in the lower, hotter zone (900–1500 K):

      \( \displaystyle \ce{FeO + C} \xrightarrow{\text{900-1500 K}} \ce{Fe + CO} \)

• Option (3) CO₂ — Incorrect. \( \ce{CO2} \) is a product of the reduction, not a reducing agent; in the hot zone it reacts with coke to give more CO.

• Option (4) H₂ — Incorrect. Hydrogen is not part of the blast-furnace charge; only coke, limestone, ore and hot air are fed in.

Note: This question is from the pre-rationalised NCERT book (2022-23). The topic is not there in the latest NCERT book (2026-27), and it is also out of the CUET 2026 syllabus.

NCERT (Pre-rationalised edition, 2022-23):
Extraction of Iron from its Oxides – “… The CO and heat moves to upper part of the furnace. In upper part, the temperature is lower and the iron oxides (Fe₂O₃ and Fe₃O₄) coming from the top are reduced in steps to FeO.”