Define activation energy Ea and explain its relation to the transition state.

• A. Ea is the energy released by the reaction, and the transition state is the final products.
• B. Ea is the energy barrier between reactants and the transition state; it quantifies the minimum energy needed for reaction.
• C. Ea is the energy of the ground state of the reactants, unrelated to the transition state.
• D. Ea is the energy difference between products and reactants, not connected to the transition state.

Answer: (B)