Ellingham Diagram — Prelims Questions

Which of the following statements regarding the Ellingham diagram is INCORRECT?

Based on a typical Ellingham diagram, at what approximate temperature range would carbon monoxide (CO) be a more effective reducing agent for iron oxides than carbon (C)?

If the Ellingham line for the formation of oxide 'A' is above the line for the formation of oxide 'B' at a certain temperature 'T', which of the following is true at temperature 'T'?

For the reaction $2M(s) + O_2(g) \rightarrow 2MO(s)$, what would be the expected change in the slope of the Ellingham line if the metal M melts at temperature $T_m$?

Given an Ellingham diagram, if the $\Delta G^\circ$ for the formation of $ZnO$ is $-300\,\text{kJ/mol O}_2$ at $1000^\circ C$, and for the formation of $CO$ from $C$ is $-450\,\text{kJ/mol O}_2$ at the same temperature, what is the $\Delta G^\circ$ for the reduction of $ZnO$ by $C$ at $1000^\circ C$ (per mole of $O_2$ removed)?

Which of the following elements would be most difficult to reduce from its oxide using carbon as a reducing agent, based on a typical Ellingham diagram?