If a reversible reaction is exothermic in the forward direction, it will be …

The correct answer is: Endothermic in the reverse direction

If a reversible reaction is exothermic in the forward direction, it will be endothermic in the reverse direction.

• Chemical processes can reach a dynamic equilibrium and are reversible.
• The location of equilibrium of a reversible reaction can be shifted by modifying the reaction circumstances.
• For a reversible reaction, one is the forward reaction and the other is considered as the backward reaction.
• The forward reactions favor the formation of products and the backward reaction favors the formation of reactants. If one of the reactions is exothermic i,e, accompanied by the release of heat then the other must be endothermic. 
• The more energy a reaction releases, the less energy is needed for the reaction to cross the energy barrier.
• The activation energy is the amount of energy needed to pass through the energy barrier.
• Hence, if forward reaction is exothermic, the backward reaction will be endothermic.