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Difficulty: MediumFactors Affecting Rates of Reaction

In a reversible reaction system, adding a catalyst increases the rate of the forward reaction while decreasing the rate of the reverse reaction, thereby shifting the equilibrium position toward the products.

Answer: Answer

Answer

False. A catalyst increases the rates of both the forward and reverse reactions equally by providing an alternative pathway with lower activation energy (EaE_a). It does not alter the equilibrium position or shift equilibrium toward products.
The statement is false. Under collision theory and chemical kinetics principles, a catalyst offers an alternative mechanism featuring a lower overall activation energy (EaE_a). This lower threshold applies to both the forward and reverse pathways equally, resulting in an equal increase in the frequency of effective collisions for both directions. Therefore, a catalyst accelerates both the forward and reverse reactions equally without shifting the equilibrium position or altering product yield.

Step-by-Step Solution

1
Analyze the kinetic effect of a catalyst on reaction activation energy.
A catalyst provides an alternative reaction pathway that reduces the activation energy (EaE_a).
The lowered energy barrier increases the fraction of colliding molecules with kinetic energy greater than or equal to EaE_a.
2
Determine how the lower energy pathway impacts forward and reverse rates.
The forward reaction rate and the reverse reaction rate both increase by the same factor.
The energy difference between reactants and products (enthalpy change ΔH\Delta H) is unchanged, so the energy barrier is reduced by the same value in both directions.
3
Evaluate the net effect on chemical equilibrium.
The equilibrium position and the equilibrium constant (KeqK_{eq}) remain entirely unchanged.
Because both forward and reverse rates are accelerated equally, dynamic equilibrium is established in less time without altering the relative concentration of reactants and products.

Key Concept

Effect of a catalyst on reversible reaction rates and chemical equilibrium
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Topics

Factors Affecting Rates of Reaction