In the presence of a catalyst, the heat evolved or absorbed during a reaction remains unaffected.

Here's why:

• Catalysts affect the reaction rate, not the thermodynamics. They provide an alternative reaction pathway with a lower activation energy barrier, allowing the reaction to proceed faster without changing the overall energy change.
• The heat of reaction, ΔH, is a state function. This means it depends only on the initial and final states of the reactants and products, not the specific path taken by the reaction. Regardless of whether the reaction proceeds through the catalyzed or uncatalyzed pathway, the change in enthalpy (ΔH) remains the same.

Therefore, while the presence of a catalyst can significantly increase the reaction rate, it does not affect the amount of heat released or absorbed.

Here's an analogy to illustrate this concept: Imagine climbing a mountain. There are two paths: a steep, challenging one and a winding, gradual one. A catalyst is like finding the easier path. You'll reach the top (products) much faster, but the overall elevation change (heat of reaction) remains the same.