Hii

Passing the neet exam depends upon the cutoff set for the particular year.
The cutoff varies for all the years.
 You may qualify your exam by securing 300 marks in total with 0 marks in chemistry (if you are above the cutoff marks) but your rank might be lower because for tie breakers chemistry marks are also considered.

I would suggest that you study hard and score well in all the three sections physics chemistry and biology to get into a good medical college.

Thanks