In a reversible reaction, the catalyst:
A. Increases the activation energy of the backward reaction
B. Increases the activation energy of the forward reaction
C. Decreases the activation energy of both forward and backward reaction
D. Decreases the activation energy of the forward reaction

Hint: If we plot the energy of a reaction against time, we will typically find a peak in the middle of the line. Maximum energy is present at this peak point, when the majority of the reactant is transformed to product. The graph then starts to decline after reaching this apex. At this stage of the process, catalysts are known to have an impact.

Complete Step by Step Solution:
A catalyst is something that accelerates the rate of reaction without being consumed by it. Catalysts frequently alter the reaction's course. Gibb's energy of that reaction is the greatest amount of work that can be extracted from a closed system. The enthalpy of a reaction is the quantity of heat a system (during a chemical reaction) absorbs or releases while maintaining a constant pressure.

The equilibrium constant for a certain reaction is the proportion of reactant to product in that reaction. The activation energy is the minimal additional energy needed for a reactant molecule to transform into a product.

Molecules react due to catalysts, which speeds up and optimises the reaction as a whole. By lowering the activation energy, this effect is produced. Therefore, we confer that catalysts always decrease the activation energy in a reaction to make it faster.
Hence, the correction option is C. decreases the activation energy of both forward and backward reaction.

Note: In nature, catalysts can be either solid, liquid, or gaseous. Increased rates of reactant to product conversion are the responsibility of catalysts. They do not, however, initiate the response. Additionally, no catalyst is utilised in the reaction; the complete amount is recovered at the conclusion of it.