A catalyst that is in the same physical state as the reactants is called what?

A catalyst that is in the same physical state as the reactants is called what?

• A. Homogeneous catalyst
• B. Heterogeneous catalyst
• C. Enzyme
• D. Inhibitor

Answer: (A)

The concept here is categorizing catalysts by the phase they share with the reactants. When the catalyst is in the same phase as the reactants—both in solution or both gases—it’s called a homogeneous catalyst. In this setup, the catalyst and reactants mix uniformly, allowing the catalyst to interact closely with the molecules and form intermediate species within the same medium, which often leads to faster or more selective reaction pathways. This contrasts with a heterogeneous catalyst, which is in a different phase (for example, a solid catalyst with gaseous reactants) and typically operates at the interface between phases. An enzyme is a specific biological catalyst, not defined by this phase criterion, and an inhibitor is a substance that slows down or stops a reaction, not a catalyst. So the best description for a catalyst in the same physical state as the reactants is a homogeneous catalyst.

The concept here is categorizing catalysts by the phase they share with the reactants. When the catalyst is in the same phase as the reactants—both in solution or both gases—it’s called a homogeneous catalyst. In this setup, the catalyst and reactants mix uniformly, allowing the catalyst to interact closely with the molecules and form intermediate species within the same medium, which often leads to faster or more selective reaction pathways. This contrasts with a heterogeneous catalyst, which is in a different phase (for example, a solid catalyst with gaseous reactants) and typically operates at the interface between phases. An enzyme is a specific biological catalyst, not defined by this phase criterion, and an inhibitor is a substance that slows down or stops a reaction, not a catalyst. So the best description for a catalyst in the same physical state as the reactants is a homogeneous catalyst.