Final answer:
The equilibrium constant, Kc, is used to determine if a reaction favors the formation of reactants or products. A Kc > 1 suggests a product-favored reaction, while a Kc < 1 indicates a reactant-favored reaction. For reactions where a precipitate forms, such as with slightly soluble salts, Kc is typically < 1.
Step-by-step explanation:
To determine whether Kc for a reaction is less than, equal to, or greater than 1, you need to consider the direction in which the equilibrium lies. A Kc value greater than 1 indicates that the reaction favors the formation of products, while a value less than 1 indicates that reactants are favored.
The equilibrium constant expression for the dissolution of CaCO3 is Kc = [Ca2+][CO32–]. Since CaCO3 is only slightly soluble, its Kc is much less than 1. For the reaction forming Ba3(PO4)2 from its ions, Ba3(PO4)2 being a solid, the Kc expression only includes the concentrations of the dissolved ions. This reaction also has a Kc < strong>less than 1, as Ba3(PO4)2 is also sparingly soluble. For the commercial production of benzene, a Kc greater than 1 would be desired to favor the formation of benzene. In the case of a titration or a precipitation reaction used in gravimetric analysis, a reaction quotient or Kc significantly > 1 is desirable as this would indicate complete or nearly complete formation of the product, which is essential for accurate measurements.