Chemical reactivity is the tendency of a species to undergo a specified chemical reaction under specified conditions. A meaningful comparison identifies the reacting partner, solvent or phase, temperature, and measured outcome.
Thermodynamic favorability and reaction speed are different: a transformation may lower Gibbs free energy yet proceed slowly because its activation energy is high. A catalyst can change that barrier without changing the equilibrium constant. Reactivity therefore connects molecular electronic structure and geometry with both chemical thermodynamics and chemical kinetics.
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