Understanding Le Châtelier’s principle fundamentals: five key questions

Abstract The well-known Le Châtelier’s principle is almost always mentioned when dealing with chemical equilibrium. Nevertheless, although a must in most general chemistry courses starting from the secondary level, when students face questions about it, some major misconceptions are often highlighted; to avoid this, a somewhat challenging problem is now presented. It can be deemed a very useful tool for a full understanding of this principle and chemical equilibrium as a whole. A generic chemical reaction at equilibrium is subject to different types of perturbation, and the student is required – in each case – to identify the new position of equilibrium among a number of proposals. The correct answers are finally provided along with the corresponding explanations.