Match each substance or chemical reagent related to iron extraction, corrosion, and qualit… — JAMB UTME

Match each substance or chemical reagent related to iron extraction, corrosion, and qualitative analysis on the left with its corresponding chemical role or property on the right.

Coke ( $\text{C}$ )Reacts with ascending $\text{CO}_2$ at high temperature to produce the chief reducing agent $\text{CO}$
Calcium silicate ( $\text{CaSiO}_3$ )Forms a molten slag layer floating on iron that protects it from re-oxidation
Hydrated iron(III) oxide ( $\text{Fe}_2\text{O}_3 \cdot x\text{H}_2\text{O}$ )Represents the chemical composition of rust formed during atmospheric corrosion
Potassium hexacyanoferrate(III) ( $\text{K}_3[\text{Fe(CN)}_6]$ )Serves as a reagent to confirm the presence of iron(II) ions ( $\text{Fe}^{2+}$ ) by forming a dark blue precipitate

Answer

Coke matches with reacting with CO2 to generate CO; Calcium silicate matches with forming molten slag to prevent re-oxidation; Hydrated iron(III) oxide matches with the chemical composition of rust; Potassium hexacyanoferrate(III) matches with testing for Fe(II) ions.

Each substance is matched directly to its chemical function: Coke supplies carbon to generate carbon(II) oxide gas; Calcium silicate acts as slag floating atop molten iron; Hydrated iron(III) oxide is the exact chemical composition of rust; Potassium hexacyanoferrate(III) is the standard bench reagent for detecting iron(II) ions in qualitative testing.

Step-by-Step Solution

Analyze the blast furnace chemical reactions involving carbon input.

Coke (

\text{C}

) reacts with ascending

\text{CO}_2

(

\text{C} + \text{CO}_2 \rightarrow 2\text{CO}

) to produce carbon(II) oxide, which acts as the chief reducing agent for haematite.

Identify the role of Coke in blast furnace extraction.

Analyze slag formation and its function in the blast furnace.

Lime (

\text{CaO}

) combines with silica (

\text{SiO}_2

) to yield calcium silicate (

\text{CaSiO}_3

), a molten waste slag that floats above molten iron.

Identify the function of calcium silicate in molten iron isolation.

Identify the chemical identity of rust.

Atmospheric corrosion of iron in the presence of oxygen and water forms reddish-brown hydrated iron(III) oxide (

\text{Fe}_2\text{O}_3 \cdot x\text{H}_2\text{O}

Match the rust formula with its physical phenomenon.

Recall qualitative analysis reagents for iron oxidation states.

Potassium hexacyanoferrate(III) reacts with

\text{Fe}^{2+}

ions to give a characteristic dark blue precipitate.

Match the analytical reagent with its specific ion test.

Key Concept

Extraction of Iron in the Blast Furnace, Rusting Mechanism, and Qualitative Analysis of Iron Ions

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