Hello,

If you want to apply for MSc or Joint MSc-PhD chemistry through IIT JAM then as per its eligibility criteria it specifies candidates to have mathematics at 10+2 level, along with having studied chemistry for three years in graduation, though you can have chemistry with CBZ combination but since you don't have maths at 10+2 level, it won't be possible for you to be eligible for the exam, kindly go through our page at https://university.careers360.com/articles/jam-eligibility-criteria for more clarity  regarding this, though I must say  you can try for other subjects in case you have interest such as biotechnology, as it's within the domain of bio group that you had at 10+2 level, and it's a booming field also, so you can appear for this subject in case you have interest for the same.