`DeltaG^@` vs T plot in the Ellingham's diagram slopes downward for the reaction

Options

A. `Mg+(1)/(2)O_(2)to MgO`
B. `2Ag+(1)/(2)O_(2)to Ag_(2)O`
C. `C+(1)/(2)O_(2)to CO`
D. `CO+(1)/(2)O_(2)to CO_(2)`

Answer

A, B, D

Explanation

Reaction (i) : `M_((s))+(1)/(2)O_(2(g))rarr MO_((s))` (where M represents metal)
Reaction (ii) : `CO_((g))+(1)/(2)O_(2(g))rarr CO_(2(g))`
Reaction (iii) : `C_((s))+(1)/(2)O_(2(g))`
`Delta G^(@) vs` T plot in the Ellingham's diagram slopes downwards for the reaction (i) and reaction (ii). For reaction (iii), `Delta G^(@)vs` T plot in Ellingham's diagram slopes upwards.