Hi Saikat Paul. Thanks for contacting Careers360 and we hope we will be able to answer your query.

As regarding to the topic weightage for WBJEE in the subject of Chemistry, according to this website, this is what we have:

• Solve questions from the NCERT books. Also, refer to the books recommended by the West Bengal Board of Secondary Education. 
• You must thoroughly prepare sections like Name Reactions, Reaction Mechanisms of Organic Chemistry and conditions under which these reactions occur.

I am unable to access the full version, but may I please share the link with you:  https://www.google.co.in/amp/s/www.toppr.com/bytes/tips-master-wbjee/amp/

Hope this helps you and all the very best! 

if you wanna learn regarding the important topics for wbjee exam.Then please read this article:

https://www.simplylearnt.com/topic-weightage/WBJEE-Engineering

Here you can prepare and practise the question as well for the important topics are here for PCM

Good luck!!!