For preparation of chemistry for your 12th board exam,i will suggest more on your textbooks rather than any other books.Make your concepts clear from your textbooks and practice numericals and organic chemistry as much as you can.As these can increase your marks.Read your textbook atleast 2 time.Be confident while appearing for exam
Good luck.

In order to prepare for chemistry you should go through your text books. Try to clear your concepts and build your fundamentals strong. 

 

If you want you can prepare your important notes which will help you at the time of revision. 

 

Go through previous year papers to understand the level of the questions. 

Focus on the topics which carries more weightage in the exam.

You can also solve MCQs for your practice.

 

Good Luck!!