With chemistry , its better to have Mathematics as a subsidiary subject. Many state Universities demand for Mathematics as subsidiary subject for the admission of MSc. Also in chemistry you will have Quantum Mechanics. So if you have Mathematics it will be easier to learn such tough topics.

Now coming to your question , Yes you can be a lecturer provided you have to pursue MSc and then PhD. After that you have to qualify NET Lectureship exam to get a full fledged job of Professor/Lecturer.

I hope my answer helps you. Wish you all the very best for your future endeavors!