(E) Estimate the energy difference (to the closest pKa unit) between Point A and Point B...

(E) Estimate the energy difference (to the closest pK_a unit) between Point A and Point B on Figure 4.15. This value is called the activation energy (E_act), the energy required to start a reaction.

a. Add a vertical arrow to Figure 4.15 indicating the size and direction of E_act for this reaction.

b. Most students assume that E_act should be +3 for this reaction. It turns out that pK_a values are useful for calculating ΔH, but not useful for calculating E_act. Assume E_act ≈ +1 pK_a unit for all acid-base reactions. Is this assumption consistent with your answers above?

(Reference Figure 4.15)