If you are asking for the free sources for Chemistry for the preparation of NEET and JEE then I can refer you to some of the youtube channels like:

• SACHIN RANA
• MADE EJEE CHEMISTRY
• ATP
• IITIAN EXPLAINS
• VINEET KHATRI
• ANYTIME PADHAI ACADEMY
• ER. DUSHYANT KUMAR
• ETOOS

You can refer for this channels if you want to study free. Now if you want to paid courses then Career360 have bring to you a great opportunity to rank high in JEE and NEET exams. The classes are taken by the experts and you will really be benefited from the course.

To know about JEE MAINS booster course visit the link below:

https://learn.careers360.com/jee-main-rank-booster/?icn=jee-rank-booster&ici=jee-text-mapping

To know more about NEET course visit the link below:

https://learn.careers360.com/neet-crash-course-rank-booster/

I hope my answer helps. All the very best for your future endeavors!