HELLO ISHAN,
If you think you have to drop a year for preparation of JEE means you can drop and that is a good decision to score good marks and to come up with the good rank in the next year.But the thing is you have to work very hard with respect to it and try to cover maximum number of problems per day,and i will refer a minimum of 150-200 problems per day in al the three subjects so that you can bang up your within 500 in jee advanced
and coming to NCERT textbook for chemistry.
If you are clear in each and every concept of organic and physical chemistry then you no need to study NCERT again.But for inorganic chemistry if also you know every concept then also you have to read NCERT for particularly inorganic
because so many problems and sentence based questions for JEE MAINS is 90% maximum from NCERT for inorganic
so please dont neglect NCERT for INORGANIC
and you have to thourough with each and every problem for physical chemistry so that type of problems may appear
and for organic chemisry i think NCERT is not necessary because in organic chemistry every problem is based on application level only so for that you can refer OP tandon or morrison boyd for that
and if you are not well with concepts then only refer NCERT for organic chemistry otherwise it is not necessary
and if you are completely i,e 100% thourough with numericals as well as concepts in physical chemistry then you can ignore NCERT
BUT please dont ignore NCERT for inorganic chemistry
MAY YOU GET GOOD SUCCESS IN BOTH JEE MAINS AND JEE ADVANCED IN 2018
ALL THE BEST TO YOU
WORK HARD
THANK YOU
