Surface chemistry is the study of chemical phenomena that occurs at the interface of two phases, usually between a gas and a solid or between a liquid and a solid. It can be roughly defined as the study of chemical reactions at interfaces. One of the important aspects of surface chemistry study is to determine whether a molecule attaches itself to a surface by chemisorption or by physisorption. Surface chemistry is of particular importance to the field of heterogeneous catalysis. It is the surface chemistry which deals with Colloidal states which finds a lot of uses.
From the IIT JEE point of view it is really easy to score marks in the questions based on this topic as the questions are direct and simple.