Application of equilibrium constant

Knowing the value of a reaction's equilibrium constant is genuinely useful -- it lets us (1) predict the direction in which the net reaction will proceed from any given starting mixture, (2) predict the extent to which the reaction will proceed before settling into equilibrium, and (3) calculate the equilibrium concentrations of the reactants and products. It is worth being clear about what the equilibrium constant does not tell us, though: it carries no information wha …