Can a teacher reveal private information about student to other students?

No, a teacher should absolutely not reveal private information about a student to other students. This is a violation of student privacy and confidentiality, and in many places, it's also a violation of law (FERPA in the US, for example). Private information includes, but is not limited to:

* Grades: Individual student grades should only be shared with the student and their parents/guardians.

* Medical information: Any information about a student's health, disabilities, or mental health conditions.

* Family matters: Details about a student's home life, family structure, or financial situation.

* Behavioral issues: Information about disciplinary actions, counseling sessions, or any other behavioral concerns.

* Personal beliefs: Religious, political, or other personal beliefs.

Sharing any of this information, even seemingly innocuous details, can lead to bullying, harassment, stigmatization, and other negative consequences for the student. A teacher's responsibility is to maintain the confidentiality and privacy of their students.