Consider the reaction between gaseous iodine and gaseous hydrogen.

\[\begin{array}{*{20}{l}} {{{\text{I}}_2}{\text{(g)}} + {{\text{H}}_2}{\text{(g)}} \rightleftharpoons {\text{2HI(g)}}}&{\Delta {H^\Theta } = - 9{\text{ kJ}}} \end{array}\]

Why do some collisions between iodine and hydrogen not result in the formation of the product?

A.     The \({{\text{I}}_{\text{2}}}\) and \({{\text{H}}_{\text{2}}}\) molecules do not have sufficient energy.

B.     The system is in equilibrium.

C.     The temperature of the system is too high.

D.     The activation energy for this reaction is very low.

A