Personal interview can be both structured and unstructured.

Structured interview – One can say with a reasonable degree of certainty that the questions are primarily confined to the candidate’s academic qualification / participation in extra curricular / awards and achievements / personal attributes like strengths, weaknesses, hobbies, special interests, family background and general knowledge.

Unstructured interview – The questions can actually come as a bolt from the blue as the IO is more interested in testing the temperament of the candidate  to see whether he or she can handle uncomfortable situations with calm and composure.