The Reaction Rates of Many Spontaneous Reactions Are Actually Very $\Delta$

Multiple Choice

The reaction rates of many spontaneous reactions are actually very slow.Which of these statements is the best explanation for this observation?

A) (K_p for the reaction is less than one.)
B) The activation energy of the reaction is large.
C) ( $\Delta$ G° for the reaction is positive.)
D) Such reactions are endothermic.
E) The entropy change is negative.