Warm wishes for choosing B.Sc in Chemistry as your career option. Now discussing about these three colleges , Xavier's College is the best option among all the private colleges, it has a good infrastructure and best ambience. But Presidency College is also a very good option but more famous for Arts Stream. JU is the best opportunity among the government colleges specially for Science Stream. I guess it works, make a wise choice!!!

Good luck !!!!

https://www.careers360.com/colleges/st-xaviers-college-kolkata

https://www.careers360.com/university/presidency-university-kolkata

https://www.careers360.com/university/jadavpur-university-kolkata