Question

All of the following are true statements regarding catalysts except which of the following?

• A. A catalyst will speed the rate-determining step
• B. A catalyst will be used up in a reaction
• C. A catalyst may induce sterics strain in a molecule to make it react more readily
• D. A catalyst will lower the activation energy of a reaction

Answer 1

The correct option is B A catalyst will be used up in a reaction

A catalyst is not used up in a reaction.
A substance that modifies the transition state to lower the activation energy is termed a catalyst; a biological catalyst is termed an enzyme. It is important to note that a catalyst increases the rate of reaction without being consumed by it. In addition, while the catalyst lowers the activation energy, it does not change the energies of the original reactants or products. Rather, the reactant energy and the product energy remain the same and only the activation energy is altered (lowered).
The relationship between activation energy $\left(E_a\right)$and enthalpy of formation $\left(\Delta H\right)$ with and without a catalyst, plotted against the reaction coordinate. The highest energy position (peak position) represents the transition state. With the catalyst, the energy required to enter transition state decreases, thereby decreasing the energy required to initiate the reaction.