Question

For the following question, the answer is an integer between 0 and 9 (both inclusive).

In the Ellingham diagram for oxides, there are x lines for the reaction(s) between C and O. What is x?

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Answer 1

See there are three distinct reactions involving Carbon. As you know, Carbon can form at least 2 oxides – $CO$ and $C{O}_2$. So then how can you expect there to be 3 separate reactions?

$C+O_2$ $\to$ $C{O}_2$

$2CO+O_2$ $\to$ $2C{O}_2$

$2C+O_2$ $\to$ $2CO$

Also, why can't we think of Carbon reducing Carbon dioxide to carbon monoxide? Please recollect that the basis of comparison for the Ellingham diagram for oxides is exactly one mole of dioxygen on the reactants' side (left).