Hello aspirant,

Please make sure that you clear the backlog of class 11th and than you can move ahead with your class 12th exams, Its not very difficult though to clear chemistry exams. All you need to do is be very thorough with Class 11th and 12th NCERT book and all the concepts in it, if you are a CBSE student, Else if from any other board than just follow your board's described book of chemistry. this will give you a good idea of the subject and than if you are able to complete the book and want to check your understanding get any solved previous year questions booklets and solve it again to check. You can always get some reference books for better understanding, but in the era of internet I dont feel you will need different books to understand anything, all the related information are present in Youtube and you can learn from it.

Happy learning.!