Which is a better course to choose whether Bsc in PMCs or Bsc in PCM after completion of 2nd pu
It really depends on your interest. But I would recommend you to go for PMCs because having a background in Mathematics and Physics or Cs and Mathematics or Cs and Physics will really help you to grow in your future in the academic or industrial fields. The area of interdisciplinary subject will increase for PMCs than PCM.
If you are really interested in Chemistry but this is my opinion about the subject combination.
I hope my answer helps. All the very best for your future endeavors!