Which series of reactions correctly represents chemical relations related to iron and its compound?

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Which series of reactions correctly represents chemical relations related to iron and its compound?

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Question

Which series of reactions correctly represents chemical relations related to iron and its compound?

A

$Fe \overset{O_{2}, heat}{\to} {Fe}_{3} O_{4} \overset{CO, 600 ° C}{\to} FeO \overset{CO, 700 ° C}{\to} Fe$

B

$Fe \overset{{Cℓ}_{2}, heat}{\to} FeC ℓ_{3} \overset{heat, air}{\to} {FeCl}_{2} \overset{Zn}{\to} Fe$

C

$Fe \overset{{dilH}_{2} {SO}_{4}}{\to} {FeSO}_{4} \overset{H_{2} {SO}_{4}, O_{2}}{\to} {Fe}_{2} {({SO}_{4})}_{3} \overset{heat}{\to} Fe$

D

$Fe \overset{O_{2}, herat}{\to} FeO \overset{dil H_{2} {SO}_{4}}{\to} {FeSO}_{4} \overset{heat}{\to} Fe$

$Fe + O_{2} \overset{Δ}{\to} Fe$

$Fe + O_{2} \overset{Δ}{\to} {Fe}_{2} O_{3}$

$FeO + {Fe}_{2} O_{3} \overset{Δ}{\to} {Fe}_{3} O_{4}$

This question tests your understanding of the chemical reactions involving iron and its compounds. Let's analyze each option step by step to identify which series is chemically correct.

Step 1: Analyze Option 1

Reaction Series: $Fe \overset{O_{2}, heat}{\to} {Fe}_{3} O_{4} \overset{CO, 600 ° C}{\to} FeO \overset{CO, 700 ° C}{\to} Fe$

Explanation:

Iron reacts with oxygen on heating to form Iron(II,III) oxide: $3 Fe + 2 O_{2} \to {Fe}_{3} O_{4}$ . This is correct.
${Fe}_{3} O_{4}$ can be reduced by CO to FeO and then to Fe. The temperatures are appropriate for these stepwise reductions. This series is chemically accurate.

Step 2: Analyze Option 2

Reaction Series: $Fe \overset{{Cl}_{2}, heat}{\to} {FeCl}_{3} \overset{heat, air}{\to} {FeCl}_{2} \overset{Zn}{\to} Fe$

Explanation:

Iron reacts with chlorine to form Ferric chloride ( ${FeCl}_{3}$ ), not Ferrous chloride. This is correct: $2 Fe + 3 {Cl}_{2} \to 2 {FeCl}_{3}$ .
However, heating ${FeCl}_{3}$ in air does not produce ${FeCl}_{2}$ ; it decomposes to ${Fe}_{2} O_{3}$ and $Cl 2$ . This step is incorrect, making the entire series invalid.

Step 3: Analyze Option 3

Reaction Series: $Fe \overset{dil H_{2} {SO}_{4}}{\to} {FeSO}_{4} \overset{H_{2} {SO}_{4}, O_{2}}{\to} {Fe}_{2} (_{{SO}_{4}) 3} \overset{heat}{\to} Fe$

Explanation:

Iron reacts with dilute $H_{2} {SO}_{4}$ to form Ferrous sulfate and hydrogen gas: $Fe + H_{2} {SO}_{4} \to {FeSO}_{4} + H_{2}$ . This is correct.
Ferrous sulfate can be oxidized to Ferric sulfate in the presence of an oxidizing agent like conc. $H_{2} {SO}_{4}$ and $O_{2}$ . This step is plausible.
However, heating Ferric sulfate does not yield pure iron; it decomposes to ${Fe}_{2} O_{3}$ and ${SO}_{3}$ . This final step is incorrect.

Step 4: Analyze Option 4

Reaction Series: $Fe \overset{O_{2}, heat}{\to} FeO \overset{dil H_{2} {SO}_{4}}{\to} {FeSO}_{4} \overset{heat}{\to} Fe$

Explanation:

Iron does not directly form FeO with oxygen; it primarily forms ${Fe}_{3} O_{4}$ or ${Fe}_{2} O_{3}$ . The first step is incorrect.
Even if FeO were formed, heating Ferrous sulfate decomposes it to ${Fe}_{2} O_{3}$ , ${SO}_{2}$ , and ${SO}_{3}$ , not to iron.

Final Answer

Only Option 1 represents a chemically correct series of reactions for iron and its compounds.

Related Topics and Formulae

Reactivity of Iron: Iron is a moderately reactive metal. It reacts with oxygen, halogens, acids, and other compounds, often forming multiple oxidation states (mainly +2 and +3).

Key Reactions:

With Oxygen: $3 Fe + 2 O_{2} \to {Fe}_{3} O_{4}$ (at high temperature)
Reduction of Oxides: Metal oxides can be reduced to the metal using reducing agents like CO, H₂, or more reactive metals. ${Fe}_{3} O_{4} + 4 CO \to 3 Fe + 4 {CO}_{2}$

Important Concept: The stability of iron compounds depends on the conditions (temperature, oxidizing/reducing environment). For example, FeO is unstable at room temperature and disproportionates.