A catalyst speeds up a chemical reaction by A. decreasing the reaction enthalpy. B. providing an alternate reaction pathway. C. shifting the equilibrium. D. increasing the activation energy.

B. providing an alternate reaction pathway

Explanation:

For a reaction to occur, the molecules of the reaction must collide with a minimum energy called the activation energy. For this reason, every reaction has an energy barrier (activation energy) to be broken for the reaction to occur.

A catalyst can speed up a reaction by lowering the energy barrier (activation energy) and the reaction will follow an alternate pathway as a result of this.

However catalyst are unchanged chemically in reaction.