Which of the following statements is true regarding the energy diagram provided?
i. The reaction is endothermic.
ii. Activation energy would be less than + 10 kJ after a catalyst is added.
iii. The reaction absorbs energy.
iv. Activation energy would be greater than + 10 kJ after a catalyst is added.

• A. I only
• B. II only
• C. I and III
• D. II, III and IV

Answer: (B)

Verified step by step guidance

1. Examine the energy diagram: The y-axis represents enthalpy, and the x-axis represents the reaction coordinate. The curve shows the energy changes during the reaction.
2. Identify the initial and final states: The initial state is at a higher enthalpy level than the final state, indicating that the reaction releases energy.
3. Determine if the reaction is endothermic or exothermic: Since the final state is at a lower enthalpy than the initial state, the reaction is exothermic, not endothermic.
4. Evaluate the activation energy: The peak of the curve represents the transition state. The difference in enthalpy between the initial state and the transition state is the activation energy.
5. Consider the effect of a catalyst: A catalyst lowers the activation energy, so if the original activation energy is greater than +10 kJ, adding a catalyst could reduce it to less than +10 kJ.