Hi.

There is no exact number of questions that should be done to be able to get 600+ score in NEET exam. It is all about practice and hard work, that a student puts into each chapter to understand its concepts, whatever number of questions it takes. For instance for a chapter you like and understood, it might be possible that you do 50 questions only and the concepts become clear but in some chapter you might have to do 70-80 questions to grasp the concept.

Good Luck