For iit what u actually require is thorrow concepts & speed calculations & not institute .
For physics h.c. verma & for chemistry ncert is must . For chemistry U may also do tata mc graw hill . For mathematics s.k. goyal is best book .
Although op aggarwal for chemistry and ml khanna for maths are good books as far as practice is concerned but would not be that much scoring as with the above books mentioned . So don't do them
First complete the above books & then revise them again . For physics U may do D.C pandey for physics but for chemistry & maths other books won't be required after that .
For Books always remember  "At the end of day what it matters is not how many  books u have done , but the book which u have done  you are thorrow with it & u must have also revised it once since to apply them in the paper not only everything should be in your mind , but u should also be able to do speed calculations  as well ".
Best of Luck for jee .
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