A non-spontaneous reaction can be carried out using the concept of coupling reaction. Explain.

Explanation

Reason which are non-spontaneous `(DeltaG=+ve)` can be converted into spontaneous reactions by coupling the former with reactions having large negative free energy. For example, the given non-spontaneous reaction is considered:
`2Fe_(2)O_(3)(s)rarr 4Fe(s)+3O_(2)(g),(DeltaG^(@))=+"1487 kJ.mol"^(-1)" ...[1]"`
Another spontaneous reaction is considered :
`2CO(g)+O_(2)(g)rarr2CO_(2)(g),DeltaG^(@)=-"514.5 kJ.mol"^(-1)" ...[2]"`
Multiplying eq. [2] by 3 & then adding to eq. [1], we get,
`{:(6CO(g)+3O_(2)(g)rarr6CO_(2)(g),DeltaG^(@)=-"1543.2 kJ.mol"^(-1)),(2Fe_(2)O_(3)(s)rarr4Fe(s)+3O_(2)(g),DeltaG^(@)=+"1487.0 kJ.mol"^(-1)),(bar(2Fe_(2)O_(3)(s)+6CO(g)rarr4Fe(s)+6CO_(2)(g),DeltaG^(@)=-"56.2 kJ.mol"^(-1))):}`
therefore, the reaction becomes spontaneous and feasible because `DeltaG^(@)` of the reaction is negative.