Hello Madan Mohan,

For the IITJEE advance paper point of view,you don't exactly need to remember all the reactions,but some reactionz which are there in the NCERT textbook would be really necessary.If you just know how a compound reacts with other compound like what type of reaction would it under go,then you can derive the products.Hence better instead of remembering the reactions crudely,you can just remember how the compounds react.Hope this has helped you.Thank You.