Match each chemical process or application involving iron and its compounds on the left wi… — JAMB UTME

Match each chemical process or application involving iron and its compounds on the left with its corresponding chemical reaction characteristic or product on the right.

Thermal decomposition of siderite ore ( $\text{FeCO}_3$ )Yields iron(II) oxide ( $\text{FeO}$ ) and carbon(IV) oxide gas ( $\text{CO}_2$ )
Reaction of iron metal with hot concentrated tetraoxosulfate(VI) acid ( $\text{H}_2\text{SO}_4$ )Produces iron(III) tetraoxosulfate(VI), water, and sulfur(IV) oxide gas ( $\text{SO}_2$ )
Galvanization of iron sheetsCoats iron with a zinc layer that acts as a protective sacrificial anode
Fluxing action of calcium oxide ( $\text{CaO}$ ) in the blast furnaceCombines with acidic silica ( $\text{SiO}_2$ ) impurity to form molten slag ( $\text{CaSiO}_3$ )

Answer

The correct matches pair thermal decomposition of siderite with production of

\text{FeO}

and

\text{CO}_2

; reaction of iron with hot concentrated

\text{H}_2\text{SO}_4

with formation of iron(III) sulfate, water, and

\text{SO}_2

; galvanization with zinc acting as a sacrificial anode; and fluxing action of

\text{CaO}

with molten slag (

\text{CaSiO}_3

) formation.

Each process matches its corresponding chemical principle: siderite decomposes into

\text{FeO}

and

\text{CO}_2

; hot concentrated

\text{H}_2\text{SO}_4

oxidizes iron to iron(III) sulfate releasing

\text{SO}_2

; galvanization uses zinc as a sacrificial anode; and calcium oxide combines with silica to form slag.

Step-by-Step Solution

Analyze the thermal decomposition of siderite

Siderite (

\text{FeCO}_3

) decomposes upon heating to yield iron(II) oxide (

\text{FeO}

) and carbon(IV) oxide (

\text{CO}_2

Transition metal carbonates decompose thermally into the corresponding metal oxide and carbon dioxide.

Examine the reaction of iron with hot concentrated oxidizing acid

Hot concentrated

\text{H}_2\text{SO}_4

oxidizes iron metal to the iron(III) oxidation state, producing

\text{Fe}_2(\text{SO}_4)_3

\text{SO}_2

gas, and

\text{H}_2\text{O}

Hot concentrated acid acts as a strong oxidizing agent rather than liberating hydrogen gas as dilute acid would.

Evaluate galvanization for rusting prevention

Galvanization coats iron with zinc metal, which undergoes preferential cathodic protection as a sacrificial anode.

Zinc is higher in the electrochemical series than iron, so it corrodes preferentially even if scratched.

Identify the fluxing action of basic oxides in the blast furnace

Calcium oxide (

\text{CaO}

) reacts with acidic sandy impurities (

\text{SiO}_2

) to form molten slag (

\text{CaSiO}_3

Slag floats on top of molten iron, preventing re-oxidation of the extracted metal while removing silicon impurities.

Key Concept

Extraction, Reaction Properties, and Corrosion Prevention of Iron

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