How is n., calculated in the question above (image attached ).. I havn`t posted whole question but having minor doubt in calculating n.. Please reply.

As there is no change oxidation state of carbon no electron needed but oxygen oxidation state chances from 0 to -2 so it need 2 electron and since total 16 oxygen therefore total 32 electron will be required so value of n is 32.Hope it clears. If u have doubts then please clearify. And if u like my answer then please approve answer

In LHS oxidation state is 0 .ok but How oxdation state is -2 in RHS, and there are 2 compounds where O2 present i.e. in CO2 and H2O.

In LHS oxidation state is 0 .ok but How oxdation state is -2 in RHS, and there are 2 compounds where O2 present i.e. in CO2 and H2O. ,i didn`t get it

In both CO2 and H2O it is -2 as in CO2 can be calculated as 4+2x =0 then x= -2 and in H2O 2+x = 0 then x= -2.Hope it clears. If u have doubts then please clearify. And if u like my answer then please approve answer