Which statement accurately describes a homogeneous catalyst?

Which statement accurately describes a homogeneous catalyst?

• A. A Pt solid in hydrogenation is a homogeneous catalyst.
• B. An acid catalyst in solution is a homogeneous catalyst.
• C. A catalyst is consumed in the reaction.
• D. A catalyst always changes the equilibrium constant.

Answer: (B)

Homogeneous catalysis occurs when the catalyst is in the same phase as the reactants, usually dissolved in the same solvent. An acid catalyst in solution fits this idea because the acid (a proton source) is present in the liquid phase with the reacting species, sharing the same environment and enabling the reaction to proceed through protonation or other proton-transfer steps within that solution. This is why the statement describing an acid catalyst in solution as a homogeneous catalyst is the best choice. It contrasts with a Pt solid used in a hydrogenation, where the catalyst is a separate solid phase and the reactants are in a different phase (gas or liquid), which makes it a heterogeneous catalyst. Also, a catalyst is not consumed in the reaction; it emerges unchanged after the reaction, so the idea that a catalyst is consumed isn’t correct. Finally, while a catalyst speeds up the reaction by lowering the activation energy, it does not alter the equilibrium constant—the final balance of products and reactants remains the same, only reached faster.

Homogeneous catalysis occurs when the catalyst is in the same phase as the reactants, usually dissolved in the same solvent. An acid catalyst in solution fits this idea because the acid (a proton source) is present in the liquid phase with the reacting species, sharing the same environment and enabling the reaction to proceed through protonation or other proton-transfer steps within that solution.

This is why the statement describing an acid catalyst in solution as a homogeneous catalyst is the best choice. It contrasts with a Pt solid used in a hydrogenation, where the catalyst is a separate solid phase and the reactants are in a different phase (gas or liquid), which makes it a heterogeneous catalyst. Also, a catalyst is not consumed in the reaction; it emerges unchanged after the reaction, so the idea that a catalyst is consumed isn’t correct. Finally, while a catalyst speeds up the reaction by lowering the activation energy, it does not alter the equilibrium constant—the final balance of products and reactants remains the same, only reached faster.