The equilibrium constant, denoted as \(k_{eq}\), is a fundamental parameter in chemical reactions. It quantifies the ratio of concentrations of products to reactants at equilibrium. Mathematically, for a general reaction: \[aA + bB \rightleftharpoons cC + dD\] the equilibrium constant is expressed as: \[k_{eq} = \frac{[C]^c[D]^d}{[A]^a[B]^b}\] where \([A]\), \([B]\), \([C]\), and \([D]\) are the molar concentrations of the reactants and products.