Question

The role of a catalyst is to change _____________ .

• A. Gibbs energy of reaction
• B. enthalpy of reaction
• C. activation energy of reaction
• D. equilibrium constant

Hint:

When a graph is plotted between energy vs time of a reaction, the peak most often is in the center of the graph. This peak is indicative of the maximum energy the reactant reaches when its conversion to product occurs.  After the peak point, the energy reduces. This is the point where the catalysts have an important role to play.

Answer 1

The Correct Option is C

The role of a catalyst is to change the activation energy of the reaction.

A catalyst achieves this by either increasing or decreasing the activation energy of the molecule. A catalyst aids in speeding up a reaction without getting self-consumed in the reaction. Catalysts can thus change the path of a reaction. Catalysts are classified into two types: Positive catalysts and Negative catalysts. Catalysts cause the molecules to react and make the whole reaction take place faster and more efficiently. This effect is achieved by decreasing the activation energy.

• The positive catalysts increase the rate of reaction by decreasing activation energy.
• The negative catalysts decrease the rate of reaction by increasing the energy of activation.

Also Read: Chemical Kinetics