alleryStart learning →A mixture has Qc smaller than Kc. In which direction will the reaction proceed?
AToward the products, raising Qc up to Kc
BToward the reactants, cutting Qc down to Kc
CIn neither direction until heat is supplied
DToward whichever side has fewer particles
Answer & Solution
Correct answer: A. Toward the products, raising Qc up to Kc
1. Equilibrium requires Q to equal K, so any gap between them drives a shift.
2. If Q is below K the numerator is too small, meaning too little product is present.
3. Making more product raises Q until it matches K, so the shift is toward the products.
4. Shifting toward the reactants would lower Q further and widen the gap.
_Source: OpenStax Chemistry (CC BY 4.0), Ch 13 "Fundamental Equilibrium Concepts", section 13.3 Shifting Equilibria: Le Châtelier's Principle_
Keep practising Fundamental Equilibrium Concepts
Browse all Fundamental Equilibrium Concepts questions for GCE A-Level (Singapore), or explore more Chemistry topics.
Related questions
Swipe each change by the way it shiftsKnock out the false equilibrium claimsFor N2 + 3H2 forming 2NH3 with Kc = 6.00 x 10^-2, [N2] = 4.26 M and [H2] = 2.09 M. What isFor 0.15 M HCN with Kc = 4.9 x 10^-10, what is the hydrogen ion concentration at equilibriWhen may the change x be neglected against an initial concentration in an equilibrium calcA quadratic solved for an equilibrium change gives two roots. How is the unwanted one recoPCl5 at 1.00 M decomposes to PCl3 and Cl2 with Kc = 0.0211. What is [PCl5] at equilibrium?For N2 + O2 forming 2NO, Kc = 4.1 x 10^-4 with [N2] = 0.036 M and [O2] = 0.0089 M. What is