Questions are generally based on NCERT syllabus. I.e. questions are directly/indirectly taken from NCERT. Sometimes the questions looks difficult or out of syllabus but if we try to solve it and apply our mind a little bit that what we learnt from NCERT.
But along with NCERT , we should use some more reference book for more practise and should solve previous year papers also. It will increase our confidence and we also will know the type of questions.
NCERT is very important, especially for Chemistry. Never neglect its exercise as most of the students do. Solve NCERT Exemplar also. Almost 60-75% of chemistry questions are from NCERT. Inorganic Chemistry to has most questions from NCERT.
Here is a list of some reference books of chemistry:
- Organic chemistry by Morrison Boyd.
- Organic chemistry by O.P. Tandon.
- The modern approach to chemical calculations by R.C. Mukherjee.
- Numerical Chemistry by P. Bahadur.
- Concise inorganic chemistry by J.D.Lee. If you are also going to coaching they will help you but if you are not going to coaching and preparing yourself then read S L Arora for physics, R D Sharma for maths, and ABC for chemistry.
Do give as many mock tests as possible.
Only reading of NCERT would not help much.