The question is a little vague so I will assume you are looking for the purpose of a basic general chemistry laboratory where various chemical solutions are mixed together in test tubes to see what is produced. One major part of doing these laboratory experiments in conjunction with a chemistry course is to try provide students with a visual representation of what they are learning in the classroom. If you have actually mixed some of these reagents together by hand and seen the color changes or the precipitates form right in front of you, then you will remember them more concretely in the classroom and on exams. On a larger level, the purpose of these labs is to try to expand on your scientific experiences. Most people will never perform chemical reactions again after finishing school, but the point is to try to show you that these chemical concepts that you are learning in class are real things and not just ideas in a book.