Question

Please explain why we have done this question this way...​

Answer 1

Answer:

Because ∆G values are additive for particular reactions. We can add or subtract values of ∆G for two or more reactions to get ∆G of target reaction.

If we talk about this question, we have three given equations and their ∆G values and we have to find ∆G values for the 4th reaction

i.e. 2ZnS+3 O2----> 2ZnO +2 SO2

if we have a look at given reactions Zns is in the second reaction but it's in the product part so we will take -∆G2 and other two reactions have O2 in reactant (as required), hence it will taken as +∆G1 and +∆G3

so finally it becomes

∆G4= -∆G2+∆G1+∆G3

hope it helps