Final answer:
In a simple distillation lab setup, usually one boiling stone is added to the distilling flask to provide smooth boiling and prevent bumping.
Step-by-step explanation:
The question relates to the number of boiling stones to use during a simple distillation process in a laboratory setting. Typically, one would add a single boiling stone to the distilling flask.
The purpose of a boiling stone, also known as a boiling chip, is to provide nucleation sites for the formation of gas bubbles, which helps to ensure smooth boiling and prevents bumping - a situation where a solution superheats and then suddenly boils over.
Too many boiling stones could lead to uneven boiling or introduce impurities, depending on the composition of the stones.