Chemistry - Metallurgy Question with Solution | TestHub

ChemistryMetallurgyEllingham diagram & Reduction methods, Refining of metalMedium2 minQB

ChemistryMediumsingle choice

Passage / Comprehension

Consider the following data:

At 25 °C:

$2 M g + O_{2} \to 2 M g O Δ G^{\circ} = - 1150 K J / m o l$

$2 C a + O_{2} \to 2 C a O Δ G^{\circ} = - 1200 K J / m o l$

At 1800 °C:

$2 M g + O_{2} \to 2 M g O Δ G^{\circ} = - 650 K J / m o l$

$2 C a + O_{2} \to 2 C a O Δ G^{\circ} = - 850 K J / m o l$

B.P. of Mg ≈1100 °C.

B.P. of Ca ≈ 1500 °C.

Which is more easily reduce by carbon :-

Answer:

Solution:

A metal oxide is more easily reduced by carbon if it has less negative ΔG° (less stable oxide).

From the given data, CaO has more negative ΔG° than MgO at both temperatures, so CaO is more stable.

Therefore, MgO is less stable compared to CaO and can be reduced more easily by carbon.

Hence, carbon reduces MgO more easily than CaO.

Stream:JEESubject:ChemistryTopic:MetallurgySubtopic:Ellingham diagram & Reduction methods, Refining of metal

⏱ 2mℹ️ Source: QB

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