If Kc = 1, which statement is true?

If Kc = 1, which statement is true?

• A. The reaction has no products
• B. The reaction has no reactants
• C. The reaction has only one side populated
• D. Significant amounts of both reactants and products at equilibrium

Answer: (D)

Kc is the ratio of product concentrations to reactant concentrations at equilibrium, each raised to its stoichiometric power. If Kc equals 1, the ratio is unity, so the expression evaluates to 1 only when both the numerator and the denominator are nonzero. That means both reactants and products are present in the mixture at equilibrium in amounts sufficient to give a balanced value of 1. Therefore, significant amounts of both sides are present at equilibrium. If there were no products, the numerator would be zero and Kc would be 0, not 1. If there were no reactants, the denominator would be zero, making Kc undefined or effectively infinite, not 1. If only one side were populated, the ratio would deviate from 1, again not matching the given condition.

Kc is the ratio of product concentrations to reactant concentrations at equilibrium, each raised to its stoichiometric power. If Kc equals 1, the ratio is unity, so the expression evaluates to 1 only when both the numerator and the denominator are nonzero. That means both reactants and products are present in the mixture at equilibrium in amounts sufficient to give a balanced value of 1. Therefore, significant amounts of both sides are present at equilibrium.

If there were no products, the numerator would be zero and Kc would be 0, not 1. If there were no reactants, the denominator would be zero, making Kc undefined or effectively infinite, not 1. If only one side were populated, the ratio would deviate from 1, again not matching the given condition.