Hey Pratik

If you have already completed your Undergraduation in any field which is chemistry in your case,you can apply for a 3 year LLB degree now if you want to pursue law. There are separate entrance tests conducted for admission into separate colleges. A few good colleges and their entrances for 3 year LLB are-

Delhi University- DU LLB

GLC Mumbai , ILS Pune etc ( MH CET)

Jindal Global Law School, IIT Kharagpur etc - LSAT

PU LLB- Panjab University, Chandigarh 

SET law- Symbiosis, Pune

And many more.

Best of luck!