A substance that increases reaction rate without undergoing permanent chemical change is a ...

• A. Spectator Ion
• B. Catalyst
• C. Oxidation
• D. Reduction

Answer: (B)

A catalyst speeds up a reaction by providing an alternative pathway with lower activation energy, so more reacting particles have enough energy to react at the given temperature. It does this without being consumed in the process, meaning the substance ends up unchanged after the reaction and can participate again in future reactions. This is what makes it capable of increasing the reaction rate without permanent chemical change.

Spectator ions, while present in solution, do not participate in the reaction and thus do not inherently speed it up. Oxidation and reduction describe electron transfer and changes in oxidation state, which are about what changes occur to atoms during the reaction, not about how fast the reaction proceeds.