Which M.Sc course should I pursue after B.Tech that is having a good scope?

Anup, I feel instead of M.Sc, better option for you would be an MBA or M.Tech Degree. If you are technically inclined then better go for M.Tech, if your interested in planning and managing then go for MBA. MBA will help your climb up the career ladder which stops after a time with M.Tech as the top

Dear Anup, As per your interest, you can take admission in chemistry branch. After completing M.Sc in chemistry, you can join as a lecturer in a college. You can join in chemical company as chemical analyst, if you want, then you can make your career as a scientist after higher studies.