Hi,

For reference books go for either of the following

1. H.C Verma (High level numerical and conceptual problems provided. This book will also help in your JEE preparations)

2. S.L Arora (basic to moderate level questions. Ideal for board examination)

3. Pradeeps (Plenty of questions to practice)

4. Exam Idea ( I use to do this as it contains plenty of conceptual questions which are more frequently asked in CBSE boards)