International General Certificate of Secondary Education (IGCSE) Chemistry Practice Exam

When the temperature is increased in an endothermic reaction, what happens to the equilibrium position?

1. Equilibrium shifts to the left

2. Equilibrium shifts to the right

3. No change occurs

4. Equilibrium becomes static

The correct answer is: Equilibrium shifts to the right

In an endothermic reaction, heat is absorbed from the surroundings, meaning that the reaction requires energy input to proceed. According to Le Chatelier's principle, if a change is made to a system at equilibrium, the system will respond in a way that counteracts that change. When the temperature is increased, the system will attempt to reduce the temperature by favoring the direction of the reaction that absorbs heat. Since the forward reaction in an endothermic process absorbs heat, increasing the temperature effectively drives the equilibrium position to the right. This shift results in the formation of more products as the system tries to balance the additional heat by favoring the endothermic reaction pathway. Thus, the correct choice indicates that the equilibrium shifts to the right.