What is the primary effect of increasing the temperature on the position of an equilibrium reaction?

Increasing the temperature of an equilibrium reaction has a significant effect on the position of that equilibrium, particularly in relation to the enthalpy changes of the reactions. According to Le Chatelier's principle, a system at equilibrium will adjust to counteract changes in conditions.

When the temperature is raised, the system will favor the reaction that absorbs heat in order to restore equilibrium. This is characteristic of endothermic reactions, which require heat as a reactant. As a result, increasing the temperature promotes the reaction that shifts in the endothermic direction, thereby leading to an increase in the concentration of products formed from that endothermic reaction.

This principle helps understand why the correct answer highlights the shift towards the endothermic direction when temperature is increased. In contrast, if the reaction is exothermic, raising the temperature would shift the equilibrium towards the reactants, as the system seeks to absorb the excess heat. Such details clarify the role of temperature in determining how equilibrium positions are affected, emphasizing the nature of the enthalpy changes involved in the chemical transformations.