A reversible reaction is said to have attained equilibrium, when
Correct answer: B. both backward and forward reactions take place at equal speed
- A. backward reaction stops
- B. both backward and forward reactions take place at equal speed
- C. both backward and forward reactions stop
- D. concentration of each of the reactions and products becomes equal
Explanation
A reversible reaction is said to have attained equilibrium when the rate of the forward reaction is equal to the rate of the reverse reaction and the concentrations of the reactants and products remain constant over time. At equilibrium, the value of the equilibrium constant (Kc) is constant, and the system is in a dynamic state, meaning that the forward and reverse reactions are still occurring but at equal rates. When a system is at equilibrium, any change in concentration, pressure, or temperature will cause the system to shift in order to re-establish equilibrium.
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About Chemical Equilibrium
Reversible reactions reach dynamic equilibrium when forward and reverse rates become equal, and Le Chatelier's principle predicts the effect of changing concentration, pressure or temperature. The chapter also covers solubility product, the common ion effect, buffer action and the conditions used in Haber's process, with equilibrium shifts distinguished from changes in the equilibrium constant.
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