Question

Out of C and CO, which is a better reducing agent at 673 K?

Answer 1

Out of C and CO, CO is a better reducing agent at 673 K. This can be explained as follows.

The CO, CO₂ curve slopes upward in the Ellingham diagram, while the C, CO₂ curve is nearly flat. At 673 K, the two curves intersect. Lower than 673 K, the response \[\ce{C_{(s)} + O2_{(g)} -> CO2_{(g)}}\] is energetically less favourable due to a lesser negative value of Δ_fG° as compared to that for the reaction \[\ce{2CO_{(g)} + O2_{(g)} -> 2CO2_{(g)}}\] which has a more negative value. Therefore, below 673 K, CO acts as a better reducing agent.