Which statement about temperature and reaction rate is true?

• A. Temperature has no effect on rate.
• B. Increasing temperature never changes the rate.
• C. Temperature increases the rate only for certain reactions.
• D. Increasing temperature generally increases the rate by increasing collisions and energy.

Answer: (D)

Raising temperature makes particles move faster, so collisions happen more often and with greater energy. Since many reactions require a certain amount of energy to get over the activation barrier, more collisions that have enough energy mean more successful reactions per unit time. That’s why the rate generally increases when temperature goes up.

The statement that temperature has no effect is incorrect because rate does change with temperature. The idea that increasing temperature never changes the rate is also false. And while there are scenarios (like enzyme-catalyzed reactions) where extremely high temperatures can reduce the rate by denaturing the catalyst, the overall trend for most chemical reactions is that the rate increases with temperature.