Which college can I get after completing class 12th from science stream? Chemistry is my favourite subject and I've always scored 90+ in it.

If you want to pursue only chemistry then you can do B.Sc in chemistry, but if you have biology too then you can do B.Sc in forensic science. If you are a non-medical student, go with chemical engineering.

You can choose an option according to your interest. And, that is chemical engineering.