Dear Aditya,
Surface chemistry is a branch in chemistry which deals with the study of the phenomenon occurring at the interface of two phases.
There is no interface between the gases as they are completely miscible with one another.
Surfaces play an active role in catalysis, colloid formation, electrode reactions, chromatography etc.
Following things are depended on phenomenon of Surface Chemistry

1. Adsorption
2. Adsorption Isotherm
3. Catalysis
4. Colloids
5. Emulsions

i hope you understand this answer.

all the best

Hello Aditya,  I think it has been done by mistake form you.
So please come with new question so that we can answer you in more better way.
I hope it will help you more.
Thanks.