Dear aspirant....!!

Yes, the questions are asked as per the order of chapters in the textbooks.

That accounts to 45–50 Questions from Std 12 Syllabus.

There may be slight variations. For instance, this year no question was asked from the chapter Metallurgy in Chemistry, leaving a 4 yearlong trend of keeping this in a list of important chapters.

This leads to 180–200 as an aggregate score. Assuming you are sharply perfect!!

However I firmly believe that most of the outcome also depends on your temperament on the day.

All the best...!