For a reaction where K > 1 at all temperatures, which statement(s) must be true?

For a reaction where K > 1 at all temperatures, which statement(s) must be true?

• A. Only I
• B. Only III
• C. Both I and II
• D. Both I and III

Answer: (A)

When the equilibrium constant is greater than 1 for every temperature, the position of equilibrium always lies toward the products at that temperature. That means, no matter what the temperature is, the mixture at equilibrium will be richer in products than in reactants. This is the statement that must be true across the temperature range. Other claims—such as how spontaneity plays out in a nonstandard mixture or exact thermodynamic details like the signs of enthalpy and entropy or the standard free energy change—don’t follow just from K being greater than 1 at all temperatures. The actual direction of spontaneity in a given sample depends on the reaction quotient Q relative to K, and while K>1 at all temperatures guarantees a product-favored equilibrium at those temperatures, it doesn’t by itself fix every other thermodynamic nuance in every set of conditions.

When the equilibrium constant is greater than 1 for every temperature, the position of equilibrium always lies toward the products at that temperature. That means, no matter what the temperature is, the mixture at equilibrium will be richer in products than in reactants. This is the statement that must be true across the temperature range.

Other claims—such as how spontaneity plays out in a nonstandard mixture or exact thermodynamic details like the signs of enthalpy and entropy or the standard free energy change—don’t follow just from K being greater than 1 at all temperatures. The actual direction of spontaneity in a given sample depends on the reaction quotient Q relative to K, and while K>1 at all temperatures guarantees a product-favored equilibrium at those temperatures, it doesn’t by itself fix every other thermodynamic nuance in every set of conditions.