Which books are best for Mains i.e. Arihant or disha and what for inorganic chemistry and what for physics?

Both of these books are good I have personally used Arihant books I found it very useful but the fact is that many questions are above the level of JEE main exams in this books so please do selective study from this books don't solve all the problems some might not be even in syllabus of the JEE MAIN.

For inorganic chemistry in JEE main you don't need to study much outside NCERT I think that NCERT is just sufficient for JEE MAIN. But don't forget to solve all the previous years question of IIT JEE.

For physics you can take help of Concept of Physics by HC Verma this is very good book, problems are very well and unique and concepts are also explain easily in a simple language try to solve all the problems from this book.