Question

Explain the following:

\[\ce{CO2}\] is a better reducing agent below 710 K whereas \[\ce{CO}\] is a better reducing agent above 710 K.

Answer 1

To Ellingham diagram, at temperature below 710 K,

\[\ce{ΔG^Θ_{(C, CO_2)} < ΔG^Θ_{(C, CO)}}\] hence \[\ce{CO2}\] is better reducing agent.

At temperature above 710 K, \[\ce{ΔG^Θ_{(C, CO_2)} < ΔG^Θ_{(C, CO)}}\] hence \[\ce{CO}\] is better reducing agent.