Hello dear student !

Though all the chapters are important in physics and chemistry class 12th and we can't predict from which chapter the examiner ask the question. But some chapters are there, which according to the previous year's papers, are predicted to have more weightage

Talking about chemistry, organic chemistry is really important. The question paper ask the direct reactions and also they carry good weightage of marks. Some chapters of inorganic chemistry are also important such as p bloc, d&f block and also electrochemistry is an important chapter. If you study these chapters thoroughly, you can get good marks.

In physics , optics contain a very good weightage of marks. Also , some more chapters like electrostatics , magnetic effect of current and magnetism , current electricity and electronic devices chapters contain a good weightage of marks.

Hope this will help you

All the best for your boards!