Hi,Yes you can pursue iit jam chemistry. And give other entrance exams for M.Sc chemistry also.

IIT jam is conducted for admissions to M.Sc. (Four Semesters), Joint M.Sc.-Ph.D., M.Sc.-Ph.D. Dual Degree, etc. Programmes at the IITs and Integrated Ph.D. Degree Programmes at IISc. The eligibility to apply for jam exam is 55%, or 5.55 out of 10 aggregate marks in their qualifying degree.

For iit jam chemistry a candidate need to possess Chemistry as a subject for three years/six semesters.

Similarly a candidate with chemistry as subject of study in bsc can apply for  jnu and bhu msc entrance exam.

Hope this helps.