hello Nayana,

No, you can't get IIT through jee mains exam rankings but you can sit in jossa counselling and could take admission  into a top nit college. For  getting an IIT college you have to appear for jee advanced and have to get a jee advanced ranks. if you had appeared for jee advanced the chances will be very high to get a rank and iit college through your reserved category.

hope it helps.

best of luck