Dear aspirant,

According to your question and taking into consideration that you want to know about the chapter polymers and you want to know it is of which lesson.

I would like to tell you that in school level in the classes 11th and 12th it is of organic chemistry and in BTech many colleges have a seperate branch for this study.

Dear student,

In chemistry ncert book, you will read the chapter of biomolecules and polymers in class 12th. This is a part of organic chemistry. And inside this chapter, you will study about different types of polymers and their uses and this chapter is also important as per jee mains point of view. Because every year 1 question is atleast asked from this chapter.
So, try not to avoid this chapter in class 12th.