A mixture of hydrogen and chlorine remains unreacted until it is exposed to ultraviolet light from a burning magnesium strip. Then the following reaction occurs very rapidly. Select the statement below that best explains this behavior.

Question

A mixture of hydrogen and chlorine remains unreacted until it is exposed to ultraviolet light from a burning magnesium strip. Then the following reaction occurs very rapidly.  Select the statement below that best explains this behavior.

Quizplus · Accepted Answer

The fact that the mixture of hydrogen and chlorine remains unreacted until it is exposed to ultraviolet light suggests that the reaction is kinetically stable, meaning that it requires a certain amount of energy input to overcome the activation energy barrier. The ultraviolet light provides this energy and allows the reaction to proceed rapidly. Therefore, choice B is the best explanation. Choices A, C, and E do not provide a sufficient explanation for the observed behavior, and D is incorrect because the ultraviolet light does not raise the temperature of the system.

A Mixture of Hydrogen and Chlorine Remains Unreacted Until It