Which of the following best describes how increasing the temperature affects the rate of a chemical reaction?

• A. It always shifts the equilibrium position toward the reactants.
• B. It decreases the reaction rate by slowing down molecular movement.
• C. It has no effect on the reaction rate.
• D. It increases the reaction rate by providing more energy for collisions.

Answer: (D)

Verified step by step guidance

1. Understand that the rate of a chemical reaction depends on the frequency and energy of collisions between reactant molecules.
2. Recall the Arrhenius equation, which relates the reaction rate constant \(k\) to temperature \(T\): \(k = A \cdot e^{-\frac{E_a}{RT}}\), where \(E_a\) is the activation energy, \(R\) is the gas constant, and \(A\) is the frequency factor.
3. Recognize that increasing temperature \(T\) decreases the exponential term's denominator, making \(e^{-\frac{E_a}{RT}}\) larger, thus increasing the rate constant \(k\) and speeding up the reaction.
4. Note that higher temperature means molecules have more kinetic energy, leading to more frequent and more energetic collisions that can overcome the activation energy barrier.
5. Understand that while temperature affects the reaction rate, it does not always shift the equilibrium position toward reactants; equilibrium shifts depend on reaction enthalpy and Le Chatelier's principle.