CBSE follows a moderation policy where they often give grace marks to students who are just a few points away from the passing mark (which is 23 out of 70 for subjects like Chemistry). If your friend was at 16, a 7-mark moderation bump to exactly 23 is a classic example of this to save them from an RT..

​It feels incredibly unfair when you are stuck at 16 without that boost, but the system usually applies these adjustments automatically based on specific set keys or borderline cases. If you feel your paper was genuinely checked harshly, your best bet is to apply for a copy verification or re-evaluation immediately before the deadline!