There are many books that you can refer to in order to understand concepts and work on problems. Below are some good recommendations:

• NCERT Chemistry for Class 11 and 12
• Physical Chemistry by O P Tandon
• Concise Inorganic Chemistry by J.D Lee
• Dinesh Chemistry Guide
• Practise books by M.S Chauhan (Organic), N Awasthi (Physical) and V.K Jaiswal (Inorganic)

Hope this helped. Good luck.

• NCERT books of Chemistry
• Textbook of organic chemistry and all medical entrance exam: by Dr. O P Tandon
• Objective NCERT at your fingertips for NEET : chemistry by MTG
• NEET Preparatory series Objective chemistry (volume 1 and 2) - Arihant