I got jee adv 2016 rank 5900.Also scored 232 in jee mains with board percentage 93.6. So should I opt iit kanpur chemistry or iit roorkee gpt or iiit allahabad it?

It is for sure, you will get placement at IIIT A in IT, but 80 % chance that you will get placement in IIT K, 50% in IIT R.
your preferences should be , Chemistry at IIT K, IIIT A IT followed by third option
Rest it depends on your interest.